The basic principles of industrial ophthalmology were developed in 1913,⁴ when the National Safety Council was formed. The National Committee for the Prevention of Blindness was organized in 1915 and sought to bring the eye hazards related to industrial occupations and ways of eliminating them to the attention of industry and of the country at large. The concerns of the National Committee for the Prevention of Blindness were not restricted to the industrial field but included the general life of our country. In the early years of the 20th century, Simeon Snell, in England, began a systematic analysis of the needs of specialized workers. Albert Snell, in this country, also pursued similar work.⁵ As industrialization reached its peak during the years of World War II, there emerged a parallel movement to improve eye safety and to introduce the discipline of industrial ophthalmology.

The Liaison Committee of the American Academy of Ophthalmology and Otolaryngology⁶ (AAOO) and the National Society for the Prevention of Blindness (NSPB) recommended that the Academy of Ophthalmology and Otolaryngology take the initiative in bringing about the formation of a conservation of vision committee. Initially this committee consisted of representatives of the three national ophthalmologic groups—the American Ophthalmological Society, the Section on Ophthalmology of the American Medical Association (AMA), and the AAOO—and of the NSPB, as the national lay organization. However, this group proved cumbersome and was dissolved. The Joint Committee on Industrial Ophthalmology was formed in 1940, with members from the AAOO and the AMA Section.^7,8

The Council of the AAOO, at their 1942 meeting, set a precedent in ophthalmology.⁷ Dr. A.C. Snell, Chairman of the Joint Committee on Industrial Ophthalmology, requested an opinion of AAOO Council regarding the advisability of appointing as associate members persons who were not members of the academy. He mentioned particularly a professor from Purdue University. It was a ruling of the chair that the officers of the committee have power to add to their committee persons who are not members of the academy. This was the first reference to the Purdue University participation in industrial ophthalmology.

The joint committee also acted as a clearinghouse for queries that came to the AMA, to the NSPB (two members of the joint committee serve on advisory committees of the NSPB), as well as innumerable queries from individuals and industries. These queries varied from questions relative to new chemicals and their effect on the eyes to testing methods, therapeutic measures, and medicolegal matters. All were checked and answered by some member of the joint committee if full information was available. Sometimes the answers were based on further investigation. One of the first medical alerts issued by the joint committee was a warning bulletin on epidemic keratoconjunctivitis in conjunction with the United States Public Health Service, which was distributed by the Industrial Health Section of the AMA at their request.

In 1943, the American Academy of Ophthalmology and Otolaryngology⁹ started publishing a section in its transactions called Industrial Ophthalmology. This section usually contained an introduction by the secretary of the joint council, Hedwig Kuhn, on the topics being considered in this journal section, as well as other activities of the joint committee. In continuing the research work on industrial visual problems, the effort had been to delineate a basic and exceedingly flexible program, which, when presented to any industry, could be streamlined to the purposes of that specific industry, making it possible for that industry to set its problems against the overall picture.

The increased tempo of wartime production had brought to light the need for good vision and of proper protection from eye hazards for industrial workers. Ophthalmic service for industrial plants, and especially for the smaller ones, was inadequate in nearly all its branches—in protection, in testing, in correcting refractive defects, in treatment of eye injuries, in recording accident data, and in the placement of employees according to visual ability and skill. However, the terminology had changed little in the first 40 years of the century—one of the biggest problems was workers' compliance.^3,10

Hedwig Kuhn is the name associated with the pioneering work in this field. Her work, Industrial Ophthalmology¹¹ was published in 1944 and was the state of the art in eye safety. Kuhn stressed the need to assess the vision needs of the worker and then to match those needs to the ophthalmic evaluation conducted for that worker. Her research at Purdue University established standards that are still in use today. These analyses defined the specific vision needs of the worker, such as the stereo acuity of crane operators and the acuity needs of a fingerprint analyzer. She summarized the key elements of the process as “(1) Selecting adequate pre-employment tests, (2) providing periodic rechecks of specific groups, and (3) conducting a practical visual survey of the plant.”¹¹

The Bausch & Lomb Optical Company¹² was one of the first to recognize the need for a full-scale eye evaluation and protection program and collaborated with others to make significant contributions. Some of these advances include

  1939 Research begun cooperatively by Joseph Tiffin, PhD, Hedwig S. Kuhn, MD, Bausch & Lomb.
  1940 Research on relationship between visual performance and job performance centered at Purdue.
  1941 Ortho-Rater developed for visual performance testing. Validity and reliability established.
  1942 Publication by Tiffin of Industrial Psychology, widely used college textbook, with first comprehensive summary of research findings.
  1943 Bausch & Lomb Industrial Vision Service introduced after 4 years of intensive research.
  1944 Adoption of Ortho-Rater for visual-performance testing by branches of military service.
  1945 Establishment of Occupational Research Center and Statistical Laboratory at Purdue University.
  1947 Development of Bausch & Lomb Consulting Services for Industrial Vision Service subscribers.
  1948 Publication of Principles of Personnel Testing, by C.H. Lawshe, Jr. It won wide acceptance.
  1948 Development of special IBM system for recording and reporting visual performance ratings.
  1948 Completed validation of Ortho-Rater visual performance tests on more than 2000 different jobs.

In the 1950s, Joseph Novak³ began a model eye safety program at the US Steel Corporation. Borrowing from the work of Kuhn, vision standards were developed for the various jobs in the corporation. Vision screening was conducted at the time of employment, and appropriate vision function was matched with the job description. At the same time, a major effort was made to put a company-wide eye safety program in place. This program provided appropriate eye safety equipment to all at-risk workers. It resulted in a dramatic reduction in workplace eye injuries. Other companies developed similar programs. Novak often said that he had accepted the torch from Kuhn and was pleased to pass it off to a new group of individuals nearly 20 years later.

THE POSTWAR YEARS TO THE PRESENT

The past 50 years has seen a dramatic change in the type of eye injuries. As the manufacturing sector eroded and the workplace changed, the nature of eye injury also shifted. Liggett and coworkers^11,13 found that in inner city Los Angeles, only 8% of eye injuries occurred at work.¹⁴ The most common locations were in the home or on the street.¹³ However, Schein and colleagues¹⁴ reported that 48% of injuries seen at an urban emergency room occurred at the workplace. This represents a wide discrepancy, and there is much discussion about the true extent of work-related eye injury. It is clear that many of the work-related injuries take place in auto repair and construction, as opposed to the heavy industrial setting seen in previous years. Statistics from Prevent Blindness America³ (PBA) (formerly the National Society to Prevent Blindness [NSPB]) estimate that there are approximately 2.4 million eye injuries each year, of which approximately 250,000 or about 10% occur at the workplace. Increasingly, children are injured while at play or while participating in sports. It is estimated that such injuries are in excess of 150,000 per year.¹⁵ The emphasis has, therefore, shifted to a more broad-based approach to eye safety. In addition, more private groups have become involved in injury prevention.

The term occupational ophthalmology was first used in 1946 by Dr. Kuhn.²⁰ She stated, “The relationship between the ophthalmologist and occupational industrial eye problems, is one of the less tangible but most vital phases of the multiple responsibilities presented to ophthalmologists by the industries in their communities. Dr. Snell had pointed out in his discussion of the ophthalmologist and its relation to occupational eye problems, some of the important aspects of these responsibilities. Let no one think that the psychology of a medical person's approach to industry and the basis of their cooperation with industry was not of first importance—it is sometimes the pivot on which all else hangs.”

In this regard, the NSPB³ (now known as PBA) has been involved in several eye safety programs. In 1948, the Wise Owl Club was formed. This organization, composed of individuals whose sight was saved by the use of protective eye wear, provides educational materials for eye safety in the workplace through 2000 chapters.³ To date, 83,699 individuals have become members. Parallel programs by the same organization have been ongoing in school and sport safety. Various other groups, such as the Hockey Equipment Council and the Little League Batter Protection program, have developed focused programs in a number of other areas that have had significant success in eliminating injuries in supervised sports.¹⁵

Recent developments in technology have given rise to several new areas of potential concern for eye safety. The association between video display terminals (VDTs) and various forms of visual difficulty led to passage of at least one local ordinance requiring ocular evaluation of all VDT workers.^16,17,18,19 As more data was accumulated, however, there was found to be no additional risk for such workers (Suffolk County, New York). The development of lasers led to the potential for significant ocular damage, and many laser safety programs were introduced as a result. Thus, each change in technology provided new challenges to which the field of eye safety has responded effectively.

In the early 1980s,³ when the American Academy of Ophthalmology (AAO) formed a committee to organize the Worker's Eye Project, planned to be a national program designed to involve ophthalmologists in the workplace. Although the project was never put into full operation for a number of reasons, one benefit was the production of an excellent teaching slide set of the same title.³ During this period, attention also was being directed to sport safety. The first course in this subject was conducted at the 1983 academy meeting. The Committee on Public Health, which was established in 1982, began to take up safety issues, one of which was BB gun control.³

The Committee on Eye Safety and Sports Ophthalmology was formed in 1989 under the chairmanship of L. Pizzarello. The committee has developed a number of programs, such as the inclusion of eye safety in the National Plan for Injury Prevention (1990), assistance with the establishment of standards for racquet sport eye safety wear (1991), a school safety curriculum for use in junior high schools (1993), and issuance of joint statements on eye safety with the American College of Occupational Medicine (1994) and the American Academy of Pediatrics (1996). This committee has worked with many other national organizations to more widely disseminate the eye safety message, including the American College of Occupational and Environmental Medicine (ACOEM), and has established the AAO as a major voice for eye safety.

1. General Background
   1. The demands that modern industry make on the eyes of its employees and the special needs of industry from the standpoint of visual performance can best be exemplified by considering the wide variance in visual requirements for such jobs as:
      1. Crane Operator—and other dangerous jobs where operation depends on precision. The span may be 150 feet, requiring not simply normal acuity but also binocular stability.
         
      2. Aviators—who must be able to call into instant action any single visual function or all visual functions, making possible the acme of perfection.
         
      3. Textile Workers and Assemblers—who on some operations work as close as 8 inches from their eyes and can do so without injury if properly selected and corrected.
         
      4. Inspectors—This field alone has now become vital to our National safety since on the accuracy of inspection depends the immediate safety of soldiers and aviators of World War II using guns, tanks, and bombs made in factories, vital, therefore, in post-war industry also.
         
      5. Clerks—The full complement of close visual skills needed by our rapidly growing number of clerical staffs cannot be replaced by International Business Machines. Clerks too are human units in this industrial effort.
         
      
      
   
   
2. Special Fields
   1. Properly defined as within the range of Industrial Ophthalmology are the following special fields:
      1. Treatment of eye injuries.
         
      2. Cooperation of the medical consultant with safety program, both for eye accidents and their prevention, and for demonstrating the relationship which certain types of defective visual functions have to accidents.
         
      3. Accident compensation and medico-legal work connected therewith.
         
      4. Diagnosis and treatment of eye diseases and the study of resultant pathology due to occupational hazards, new toxic substances, fatigue factors, strains in aviation, vitamin deficiencies in night work, etc.
         
      5. Consideration of visual problems directly related to ocular function (cataracts and macular degeneration)—acuity; stereopsis, phoria, etc. The medical procedures when carried further, include also:
         1. Study of occupations, distance of work, particular demands for binocular function, position of machinery, cross lighting, etc.
            
         
         
      
      
   
   
3. Essentials of Visual Function
   These are important to safety, health and efficiency of industrial workers. (Now mandated by the Americans With Disabilities Act of 1990).
   
4. Technique of Testing
   Factors should be utilized in the selection of technique and clarification of the most practical techniques for all conditions and all plants.
   
5. General Visual Standards of Admission for All Classes of Jobs
   There are different requirements for different classes of jobs, i.e., dangerous jobs requiring efficiency and accuracy or critical jobs involving close work regarding special performance vs. jobs demanding less rigid standards.
   
6. Modern Plant Program
   1. The Ophthalmologist's Role: There must be cooperation between management, the company or plant doctor, and the consulting ophthalmologist. In setting up a practical program the ophthalmologist must have knowledge of the specific industry, its needs, jobs, work conditions, and unusual problems. Some important considerations are:
      1. Familiarization with organization and management and physical layout of plant.
         
      2. Consideration of such allied problems as:
         1. Lighting (glare because of new chrome fixtures, big windows, special lighting, white wall, etc.)
            
         2. Goggles Program: Corrected vision hardened lenses should be advised instead of “cover-alls.” Effort should be made to have management consult medical staff in goggles problems, rather than commercial sales organizations or lay safety directors only.
            
         3. New “three dimensional seeing” (sense of depth of perception) work of duPont, increasing safety and efficiency through new painting technics of machinery and streamlining, with emphasis on working fields, color contrasts, etc.
            
         4. Servicing ophthalmic lenses and protective goggles.
            
         
         
      
      
   2. Re-examination of Special Groups. The frequency of re-examination depends on:
      1. Type of work—Those doing dangerous and demanding jobs should have periodical re-examination.
         
      2. Age—Presbyopic personnel, especially in critical positions, may be affected by medications or other medical conditions that affect the eye and should be among those re-examined. Color discrimination decreases with age and therefore should be retested when color is important to production.
         
      
      
   3. Interpretation of Defects in employees in any one industry or plant need not be fixed but should be flexible enough to meet changing conditions of industry, and placement should be recommended in accordance with changing visual functions of employees.
      
   4. Rehabilitations—These should consider:
      1. Gross defects.
         
      2. Borderline defects in dangerous jobs.
         
      3. Borderline defects in jobs demanding accuracy.
         
      4. Occupational Orthoptics.
         
      5. Occupational eye wear—Special close work problems (12 to 8 inches or at 20 to 30 inches) requires refractive expertise.
         
      6. Vitamin deficiencies and possible depletion of visual pigments in certain occupations was another problem.
         
      
      
   5. Accident Studies: All serious accidents, whether to the eye or to other organs should be analyzed for evidence of visual ocular function deficiencies. The records taken at the time of an accident should include information on lighting, time of day, general nervous tension, work shifts, home conditions, etc.
      1. Accident analyses should include suggestions regarding prevention.
         
      2. Individuals with low acuity or other visual defects should be identified and each case be evaluated by the medical office before being transferred from one job to another. Attempt to place them only in positions where they can fulfill their essential functions without significant risk or direct threat to themselves or to others.
         
      
      
   
   

THE PROSPECTIVE WORKER

To apply the preplacement examination findings, a detailed knowledge of the job is a must. Such information is derived from a visual analysis of the occupation.²²

These data, or visual skills demanded of the worker, are written into the job requirements and meet with eventual tabulation.

This visual survey must be accomplished by the ophthalmologist so that he or she can get into the shops, know the jobs intimately, learn the shop language, and be completely familiar with the workers' daily environment. From this point on, the ophthalmologist is of immeasurable aid to the medical director and the personnel director who are trying to place a certain individual in a certain job, where full use of his or her capacities will be attained.

From information gained at the time of the visual analysis the eye protection required by the job is provided the worker. This is in the form of safety glasses, containing optical correction if needed, which offers protection against impact through use of special lenses. Through a single implementing device, a two-fold occupational result is obtained, specifically, good working vision and eye protection. To prescribe the proper lenses, a knowledge of the job is necessary, for occupational glasses carry with them a visual potential based on the working distance and a safety defense determined by the hazards characteristic of the job.

Each person applying for a position in large or small plants should undergo a complete physical appraisal. A part of this preplacement survey is the vision (ocular) screening procedure, which in the more progressive plants, consists of a battery of tests supplied by a single screening or rating instrument. This is a far cry from the reading of a Snellen chart, badly illuminated, badly worn, badly distanced, and badly interpreted. The basic tests offered to the new employee will help determine the worker's ability to meet the job's physical demands.²² The results from these procedures are then, in a well-integrated program, matched against the visual requirements of the job. Failure to meet the guidelines established for that particular job will place the worker and management at risk both from a safety and production standpoint. It is in this role that the ophthalmologist plays so keen a part, by interpreting from these tests the visual skills of the applicant. In large plants the ophthalmologist interprets the findings of testing done by nontechnical personnel (ophthalmic personnel, occupational nurses), or in small organizations the ophthalmologist will do the examining or the tests will be done by the primary care physicians. Data is used in cooperation with the medical and personnel directors to place that person in a job—actually fitting the eyes to the job.

THE EMPLOYEE IN HEALTH

In addition to evaluating prospective employees, follow-up and survey studies should be initiated. Workers should be checked for glaucoma, degenerative diseases of the retina, lenticular changes, and fundus evidence of systemic disease.

Diseases of the eye that are detected can be followed for further change or can be corrected if possible or recommendations can be made to management for a change in the employee's job. Rehabilitation of the limited worker is a phase of industrial health to which the ophthalmologist can contribute so much.

Visual health is maintained further by studies of illumination, machinery and desk placement, color as it applies to the equipment used, and the surrounding environs. Through the elimination of glare, malplaced and maldesigned dials, color clashes, poor contrasts for night work, and other sources of fatigue, the worker is kept in optimal visual health.

ANALYSIS OF THE WORKPLACE VISION REQUIREMENTS

Kuhn²³ has suggested that three main objectives are required for an industrial eye program: (1) conducting a practical visual survey of the plant, (2) selecting adequate pre-employment tests, and (3) providing periodic rechecks of special groups.

Kuhn²³ stated, “An essential and as yet hardly touched part of an intelligent appraisal of industrial eye problems, is a detailed visual job analysis. To know what a given pair of eyes must be able to do in order to place new employees according to their visual skills; in order to correct any defect properly for that work (if refractive correction is indicated); in order to choose the right type of protective equipment, one must see each and every job and codify its essential characteristics.”²³ Tiffin and Wirt,²⁴ in their Purdue University Study, analyzed the relationship of accident-free performance and visual test requirements. They suggested that there must be minimum requirements or standards of performance on the visual examination that may be demanded of any employee who is assigned to such jobs. Stump²⁵ reviewed employees' visual performance and compared them with visual standards. He reported a 106% increase in accidents with extreme deviation from the standard, 43% with moderate deviation, and 31% with negligible deviation from the standard. In 1942, Dr. Albert Snell⁵ stated “good vision is that degree of visual function ability which is adequate to perform the visual task presented.” Clearly, visual function is an important factor in safety, and its improvement will allow a reduction of accidents. Studies of visual skills in relation to job performance in many types of work by Kuhn,²³ Tiffin and Wirt,²⁴ Stump,²⁵ and others suggest that visual skills are one of the most universal and frequent factors affecting job performance. In fact, work success can often be predicted, to some extent, on the basis of visual skills such as acuity, muscle balance, and near vision.

Tiffin, in his textbook Industrial Psychology,²⁶ noted that the Joint Committee on Industrial Ophthalmology suggested that there must be some minimum requirements or standards of performance on the visual examination. Kuhn²³ proffered the concept of differentiating between separate visual standards and their relationship to the requirements of a given job. Visual requirements for employment on certain jobs or in certain plants have been established by the following^3,27: (1) observation methods—standards established regarding types of testing to be used and levels of performance required for specific jobs, based on direct and expert observation of the job in question, when available or (2) statistical methods—evaluation of available facts that help determine which tests and what minimum levels of test performance most adequately identify the worker who is potentially better on a specific job.

Tiffin²⁶ developed vision requirements to best employ, efficiently and safely, the available manpower in the 1940s. The Americans With Disabilities Act²⁸ (ADA) of 1990 was implemented in July of 1992. It covers the hiring of employees who can fulfill the essential functions of a position, with or without accommodation, without significant risk or direct threat to oneself and to others. The purposes of both efforts are similar but approach the issue differently. In fact, it was not until passage of the ADA that a legal requirement existed for matching individual capabilities with job requirements.

Visual Requirements of Jobs

Jobs differ in visual demands they make on a worker.²⁶ Such variations are both qualitative and quantitative. Consider the job of a crane operator. The worker is required to see clearly at a distance of 60 to 100 feet to set down the load accurately and within a narrow prescribed area. Compare the demands of that job with those of some assembly lines, where a worker may be required to see clearly materials at a very close distance to fit together quickly an intricate system of small parts and wires. The job of crane operator demands that a worker can see detail at a great distance. The ability to differentiate such detail close up is of much less importance to the job. Assembly, on the other hand, reverses the importance of these two types of visual skills. This job requires acute and comfortable vision at close range and relatively less need for such visual ability at greater distance.

The optimal use of visual skills tests for the selection and placement of industrial workers requires an accurate method of determining both the type and quantity of visual skills demanded by various industrial jobs. Mere observation of the job activity may not allow adequate determination of visual requirements. Usefulness of such tests can, however, be established by other techniques described below.

OBSERVATION TECHNIQUE

Visual Task Analysis

Before the vision screening for a worker can be recommended, there should be an analysis of the visual tasks required by the job. Analyzing the visual factors required for a task is of crucial importance.²⁹ Ideally the analysis should be performed at the place of work (e.g., the factory or office). Factors, such as distance and size of the critical details of the task, should be assessed, along with need for color discrimination; depth perception; body, head, or eye postures; field of vision; eye movement requirements; and the contrast and illumination at the job site. Important visual factors can be identified in this manner, and this analysis fulfills regulatory requirements of the ADA²⁸ and Occupational Safety and Health Act [Occupational and Health Administration (OSHA)] 29 CFR 1910.132.³⁰

A plant “walk-thru” offers the opportunity for the physician to accomplish several tasks. Plant illumination lighting and the visual requirements of specific jobs can be scrutinized. General hygiene and compliance with necessary personal protective equipment (PPE), such as safety glasses, can be noted. The OSHA log can give valuable information about injury patterns. Safety equipment, such as eye wash booths, can be inspected.

North developed a useful job checklist (see Table 1) for the analysis of visual requirements for each job in the workplace. It entails a careful survey of each component of a given job in relation to the employee's visual skills used in the performance of his or her tasks.³¹ This analysis requires a broad knowledge of visual abilities and limitations (problems of accommodation, convergence, presbyopia, coordination, muscle balance, etc.) lighting, physical factors, and the host of eye hazards of the particular operation. The visual survey is best accomplished as a cooperative venture that may include contributions from the plant medical director; the consulting eye physician; production, illumination, and safety engineers; the personnel director; and supervisors. In some instances, one person with unusual knowledge and experience can qualify and evaluate these various skills. Proper vision is an important factor in industrial efficiency and has a marked bearing on output and on safety. Adequate measurement and classification of visual requirements of a job is one of the most effective means of determining the potential efficiency of applicants for jobs. By the same means, it is possible to increase the efficiency of employees on the job.

TABLE 1. Check List of Visual Job Analysis

1. Job description (including qualifications relative to type of training and skills) with standard code number.
   
2. Distance or distances (distance for acuity and/or near acuity) in inches or feet from eyes of worker to point of operation, fixed or changing.
   
3. Motion of work (distance and near muscle balance): slow or rapid rotation, vertical or horizontal, fixed or intermittent.
   
4. Size of central working area, depth perception factors (stereopsis).
   
5. Type of visual attention required: fixed or changing, casual or concentrated, detailed or gross (or listed as perfect, average, or defective permissible; or as class A, B, or C).
   
6. Colors to be perceived and discriminated.
   
7. Foot candles of illumination at workpoint, as well as in surrounding area. Direction of light (note any harmful shadows). Reflected or direct glares (to be eliminated if possible). Brightness ratios (avoid sharp contrasts).
   
8. Color of light source and work area (functional painting, etc.).
   
9. Type of working surface: glossy or nonglossy, slightly or grossly uneven. Angle of working surface. Position of work in relation to normal level of eyes, viz., does worker have to look down, ahead or upward (determine whether bifocals are permissible or a handicap).
   
10. Eye hazards: flying objects, particles of dust, fumes, splashing chemicals, or molten metal; airborne matter; radiation, and so forth.
    
11. Type of eye protection required.
    

VISUAL ERGONOMICS OF THE OFFICE WORKPLACE.

Visual symptoms can usually be resolved with a combination of ergonomic changes in the environment and the provision of appropriate visual care to the computer worker (Fig. 1). Studies indicate that visual complaints occur in 50% to 90% of workers who use VDTs.^{17,19,32,33,34} These problems result from visual inefficiencies or from eye-related symptoms caused by a combination of individual visual abnormalities and poor visual ergonomics. The problems occur whenever the visual demands of the task exceed the abilities of the individual.³⁴ Such difficulties are real and prevalent. The basis for most of the problems is understood.

The ability to perform most tasks depends on many visual and nonvisual variables.²⁹ The factors that influence the visual performance include the visual capability of the individual, the visibility of the task, and psychologic and general physiologic factors. However, such factors must be considered because they can significantly influence visual performance. It is not within the scope of this chapter to deal with the third group of factors in depth, although psychologic and general physiologic factors, such a motivation, intelligence, general health, and so forth should not be forgotten, because they can all influence the visual performance. This chapter deals in detail with the first two variables—visual capabilities and the visibility of the task.

Ergonomic Tactics to Prevent Visual Fatigue and Other Visual Disorders

Visual fatigue is a term used to describe phenomena related to intensive use of the eyes. It can include complaints of eye or periocular pain, itching or burning, tearing, oculomotor changes, focal problems, performance degradation, “after colors,” and other phenomena.³⁵ There are ergonomic tactics that can be used to prevent or reduce visual fatigue.

Ergonomic research supports the following regarding VDTs:

• Placement of frequently used displays in the primary visual display area. The top of this area should be opposite the operator's eyes, with the eyes facing straightforward, extending down to a point at which the operator is looking down at a 30-degree angle. Devices viewed as they are operated, such as buttons, keyboards, and controls, should be above and below this area, at the work surface, and above the plane of the operator's eyes.
  
• The optimal viewing distance for visual displays is about 50 cm, or 20 in. Corrective lenses designed specifically for the job can be used for workers with refractive error or presbyopia. Lenses of this type can be incorporated into multifocal eyeglasses (progressive add lenses with overviews) as well.
  
• Proper illumination is important. It should be evaluated for each task.
  
• Visual performance can be impaired by whole-body vibration in the range of 10 to 25 cycles per second. Such vibration, which may be generated by power saws, cranes, conveyors, and other machinery, should be damped or separated from the worker.
  

The Visibility of Tasks

The ability to perform a task safely, efficiently, and comfortably depends on its visibility, as well as on the visual capabilities of the employee, as outlined.²⁹ Naturally, the better the visibility, the easier it is to perform the task. The factors that influence the visibility of a task are

1. Size of task.
   
2. Distance of task.
   
3. Illumination.
   
4. Glare.
   
5. Contrast.
   
6. Color.
   
7. Time available to view task.
   
8. Movement of the task.
   
9. Atmospheric conditions.
   

SIZE OF TASK.²⁹

The size and critical detail of the task must be taken into account so that the angle subtended at the eye, and hence the visual acuity necessary to perform the task comfortably and efficiently, can be calculated. The retinal image size of any object is inversely proportional to its distance from the eye. Therefore, objects may differ greatly in physical dimensions but form similar retinal image sizes because they are viewed at different distances. Although the visual acuity may be the same, the demands made on accommodation and convergence may be different (Fig. 2). A very small object may have to be placed very close for the detail to be large enough to be resolved, but this will require good accommodation and convergence.

Static Acuity.

Static acuity is the capacity for seeing distinctly the details of a stationary object. This should be related directly to size and distance of the smallest detail required to be seen in the assigned task. Numerous factors, according to North,²⁹ can influence the ability of the visual system to see details. These include luminance, contrast, spectral nature of light, size and intensity of surrounding field, region of retina stimulated, distance and size of object, time available to see object, glare, foggy or steamy atmosphere, refractive error, pupil size, age, attention, IQ, boredom, ability to interpret blurred images, general health, and emotional state.^36,37

The choice of safety glasses is especially critical for individuals who have a loss of accommodation (presbyopia) or must use contact lenses in the workplace. A presbyopic lens should provide for the lack of accommodation so that the user can perform visual tasks efficiently and effectively in accordance with the essential functions of the position. The occupational presbyopic lens should attempt to mimic the normal accommodative process and provide a physiologic amplitude of accommodation. The occupational eye care provider should prescribe lenses to allow the performance of essential visual tasks (Fig. 2) comfortably with good visual and body ergonomics.

Vernier Acuity.

The type of visual acuity discussed so far has been form acuity—the ability to discriminate between two small parts of an object. However, in some occupations line detail is required, for example, the use of micrometers or precision gauges requires the discrimination of a break in contour or alignment, that is, vernier acuity. The visual system is extremely sensitive to these details and it is approximately one twentieth of the corresponding angle for details to be resolved in form acuity.³⁸ If the form acuity for a certain distance is known, then it is relatively easy to calculate the equivalent visual angle for vernier acuity and the actual size that may be resolved and vice versa. Misalignments of segments of a divided line of approximately 3 seconds of arc can be detected at moderately high levels of illumination, whereas the minimum angle of resolution is between 30 to 60 seconds of arc.³⁷

CONTACT LENSES IN THE WORKPLACE.

The AAO and ACOEM Joint Policy of Wearing Contact Lenses in the Workplace stated, consistent with the ADA,³⁹ that individuals should not be disqualified from performing their essential functions in an industrial environment because they wear contact lenses unless it can be proved that they pose a direct threat and substantial risk to the health or safety of themselves or others in the workplace. The 1998 revision of the Code of Federal Regulations on Respiratory Protection allows for contact lenses under a full-face respirator.⁴⁰ Although contact lenses provide some protection, they do not fulfill the ocular safety standards, so the required industrial safety eyewear for the specific hazard identified in American National Standards Institute (ANSI) Z87.1⁴¹ must be worn over them. Blais^27,42,43 has provided evidence that contact lenses are neither a direct threat nor a substantial risk in the hazardous environment.

There are numerous other factors, according to North,²⁹ that physical, physiologic, and psychologic, which can influence the ability of the visual system to see details. These can be listed, in addition to the previous list, as follows: spectral nature of light, intensity of surrounding field, region of retina stimulated, distance and size of object, foggy or steamy atmosphere, refractive error, pupil size, age, ability to interpret blurred images, and general health. The following should be considered under the category of psychologic and physiologic: attention span,³⁶ IQ, boredom, and emotional state.³⁷

DISTANCE OF THE TASK.²⁹

Naturally, the distance of the task from the observer and the size of the detail of the task affect the retinal image size, and hence the visual acuity required to distinguish it. The distance of the task also determines the level of accommodation and convergence and the degree of uncorrected refractive error or phoria that may be tolerated. Working distances may be classified as: far (greater than 2 m), intermediate-to-near (less than 2 m and greater than 30 cm), and very near (less than 30 cm).³⁸ Examples of tasks involving far working distances include driving a vehicle and flying an airplane; intermediate-to-near tasks include secretarial work, VDT operation, and lathe operating; and very near tasks include sewing, micro-electronics assembly work, and watch repairing (see Fig. 2).

The amount of accommodation decreases with age and after their mid-40s workers require a spectacle prescription to focus near objects clearly and comfortably as the range of accommodation reduces with age; the range of clear vision through the near vision addition becomes smaller. Workers with poor visual acuity may also benefit from increased lighting levels and from more magnification to increase the retinal image size.^33,44,45

ILLUMINATION.

Proper illumination is important and it should be evaluated for each task. The relationship between illumination on the task and performance achieved will vary according to the type of task.²⁹ The effect of illumination on task performance will vary according to

1. The visual difficulty of the task.
   
2. The extent to which the visual part of the task determines the overall performance.
   

The greater the visual difficulty, the greater the effect of the illuminance, whereas in a task such as audio typing, in which there is only a small visual component, the effect of illuminance on the overall task performance will be small. It is dependent on the needs of the task, reflectance of surfaces in the area, and, to some extent, the age of the worker. Older workers generally require brighter lighting for visual discrimination. In general, illuminance of 70 to 80 foot candles (ft-c) is needed for general office work, 100 to 150 ft-c for visually intensive tasks, and up to 500 to 1000 ft-c for very fine tasks.²⁹

GLARE.

The effect of veiling reflections and the complexity of the task have a significant effect on job performance.²⁹ Veiling reflections are due to light from a high luminance surface, such as a luminaire, being reflected from a specular surface, which is being viewed. These veiling reflections cause a reduction in performance because of the decreased contrast created on the task by the superimposed reflections.

Lighting geometry should be configured to avoid glare. Glare on a VDT screen, for example, should be reduced by

• Placing visual display terminals out of direct line with or facing windows.
  
• Using window films and coverings.
  
• Using dull, textured surfaces.
  
• Reducing ambient lighting to below 500 lux (18 to 46 ft-c) and using supplemental lighting where needed.
  
• Using indirect lighting.
  
• Using parabolic louvers on fluorescent lights.
  
• Shielding of auxiliary lighting.
  
• Using eye shades.
  

Visual discomfort from glare and other sources accumulates during the work day, and task rotation may be a reasonable preventive measure if other adjustments are not successful.

CONTRAST.

The eye detects objects by responding to the differing levels of illumination at the target edges, or contrast²⁹:

Contrast = <fr background illumination - target illumination/background illumination>

To determine the optimal illumination levels for a task, the contrast and size should be measured. It is difficult to measure the contrast of a practical task. These vision standards, either mandatory (e.g., DOT) or voluntary (Purdue Standards), apply to tasks of normal contrast and reflectance. If, however, the contrast or reflectances are low and mistakes are made because of wrong perception, these are likely to be dangerous or costly. The recommended illumination should be increased to compensate for the decrease in contrast of the object considered.

Concerns regarding the visibility of tasks have influenced the American codes for lighting.⁴⁶ The initial experiments carried out investigated the threshold detection of static disc targets, and later experiments involved the detection of dynamic targets. The dynamically presented targets were believed to create conditions more similar to a practical task. More recent studies have investigated the effects of lighting on the visual performance of a 20- to 30-year-old age group.⁴⁷ Older individuals require more light than younger ones to perform a similar task.²⁹

COLOR.

Deficiencies can be either congenital or acquired. The ability to discriminate colors is particularly influenced by age and illumination. It has been shown that with age there are more errors in hue discrimination in the blue-green and red regions.⁴⁸ This study showed that the number of sorting errors in the FM 100 hue test could be reduced by increasing illumination.^48,49

TIME AVAILABLE TO VIEW TASK AND MOVEMENT OF THE TASK.

The time available to see the task is important; too short a time exposure will reduce the visibility, especially if the task is moving.²⁹ The time available to view the letters and so forth will influence the visual acuity measured. It has been estimated that a person can transmit up to 10 bits/second (a bit is a unit of information processed in a second) of visually displayed information. This is a very small amount of information, when it is estimated that the human sensory system has a capacity to transmit millions of bits per second. Therefore, it is not only the input of the visual system that limits the visual performance but the processing, decision making, and motor output. Letters can usually be recognized in under a second, and, obviously, the better the illumination and the larger the letter, the faster the recognition time.

ATMOSPHERIC CONDITION.

Atmospheric conditions in such industries as foundries and mining, in which there may be dust, smoke, or steam, will reduce visibility because of the absorption of light.²⁹

Interactions of Luminance, Contrast, and Glare

Three major factors that influence visual acuity are luminance, contrast, and glare. The influence of luminance on visual acuity may be plotted (Fig. 3). The capacity of the visual system to resolve details increases with increasing luminance, although there is a level beyond which visual acuity does not increase; in fact, it may diminish because of disability glare. Contrast has a maximal effect on visual acuity at low levels of illumination but has a minimal effect at high levels.

Spalton and colleagues,⁵⁰ in their slide atlas of ophthalmology, state that the graph of visual acuity plotted against contrast shows the rapid improvement in acuity as contrast increases and the difference that background illumination makes to the acuity under the same conditions of contrast (Fig. 4). In clinical acuity tests black letters are displayed on a white background giving a contrast value of approximately 80%. In the normal eye under photopic conditions the threshold contrast is about 1%.

The following example relates the association of distance and decreased contrast. The eye with a visual acuity of 20/40 visualizes a 1.0 mm-target at 14 in. (35 cm). At 28 in. by doubling the distance without change in size, the eye will require a visual acuity of 20/20 with high contrast. Using Figure 4, working at moderate contrasts would require a visual acuity of 20/05, a visual acuity not readily available in most human beings. In essence, doubling the distance doubles the visual requirement, and decreasing the contrast also doubles the visual requirement.

Visual Factors for Specific Task

There are occasions when on-site analysis is not possible. A logical method for determining the visual factors required for a particular task was devised by Grundy.⁵¹ From the knowledge of the distance and size of the critical detail of the task, the visual acuity necessary to discriminate the smallest detail can be determined. This can be calculated easily from a simple graphical method by using a nomogram, shown in Figure 5. For example, a task has a critical detail of 0.6 mm and is viewed at 70 cm. When a straight line is drawn through these values it will intercept the right-hand scale to indicate that the corresponding visual angle is 3.0 minutes of arc and the minimum visual acuity required is 6/18. It is important to remember that the values given are a measure of the resolving power of the eye, and higher standards are required for the task to be carried out for prolonged periods. It has been suggested that the visual acuity necessary for a demanding task should be approximately twice the minimum value.⁵² Therefore, in the previous case, a visual acuity of 6/9 is advised. The employee can often move closer to the task, increasing the angular subtense at the eye, but this depends on the amount of accommodation and convergence available. The older presbyopic employee, who has a reduced amount of accommodation, may need an intermediate and a near prescription, depending on the distance of the task.

Steps in Setting Standard—Observation Techniques

After analysis of the visual task in which the important visual factors are determined, a standard can be set by either: (1) choosing a standard believed to be necessary to work efficiently and safely, for example, VA 6/12, distinguish principal colors—for red, green, blue, and yellow hues. This can be tested by relating visual competence to job competence as described previously; or (2) insisting on the normal level of visual capabilities for each factor chosen, for example, VA 6/6, normal color vision (red and green hues). This approach would exclude some who were capable of performing the task comfortably yet could not meet the selected standard.

STASTICAL METHODS

Joseph Tiffin and his associates of the Division of Education and Applied Psychology, Purdue University and the Bausch & Lomb Industrial Vision Services,²⁶ used a statistical basis to solve problems of visual standards. A number of existing employees on specific jobs—employees of all degrees of ability and achievement—were tested. These employees were classified on the basis of production, quality rating, or other available measures of job success into categories that ranged from “definitely superior” to “definitely inferior.” The visual characteristics of the different groups were compared to determine how visual skills of the superior workers compared with those of inferior workers. Because measurements of job performance are influenced by the amount of training and experience on the job, as well as by aptitudes and skills, careful handling of the data was required.

Visual-skill records of more than 150,000 employees associated with more than 200 companies were tabulated and analyzed. These employees occupied more than 2000 different jobs. Wherever possible, individual records of job performance were obtained for each employee. Visual-performance test scores and job-performance results, as well as a record of age, experience on the job, sex, and other pertinent facts, were recorded and tabulated.

The visual-performance requirements for each job were determined from the resulting analyses. Employees with substandard visual performance were identified and referred by their employing company to local practitioners.

VISUAL STANDARDS

General

The purpose of visual screening tests as part of a job evaluation is to compare the visual performance level of an applicant to the demands of the job.²³

Statisticians have shown that careful study of the visual skills found to be associated with successful employees can predict the future success of comparable applicants. On this data, the actual basis of pre-employment standards are built. Medical people are trained on the whole to deal with sick and/or defective and physically unimpaired people. Their approach to examinations of a physical organ, such as the eye, and its relationship to a given task, is to think of the defects that prevent a person from doing that task. They seek to separate out misfits. The psychologist and the statistician separate out those who are successful. They are interested in finding those who have the physical skills to fit the requirements of a given task. They are interested in those who do qualify, whereas doctors are interested in discovering those who do not qualify. It is important to keep this distinction in mind. If thoroughly understood, it forms the basis for a much clearer understanding between groups who need to work more closely together, namely, statisticians and doctors.^53,54

Vision and Job Proficiency

Studies of visual skills in relation to job performance by Kuhn,^21,23 Tiffin and Wirt,²⁴ Stump,²⁵ and others in diverse work environments have demonstrated that various visual skills frequently affect job performance. The importance of adequate vision in industry can be satisfactorily demonstrated only in relation to acceptable industrial criteria, such as hourly production, the proportion of work rejected for defective workmanship, supervisors' ratings of employees, employee absences, rate of labor turnover, or other measurable aspects of an employee's value to the company.⁵⁵ Vision characteristics that correlate with these industrial criteria differ from job to job and cannot consistently be predicted without correlating evidence. There are many qualities of the worker's performance on the job that contribute to his or her degree of job success.⁵² The most obvious aspect of job success is the amount of work produced by the individual within a given time. Individuals vary in the number of pieces they can produce per hour even though they are working on identical machines and may appear to be working under identical job conditions. Visual skills are one of many factors that contribute to this difference. Visual skills that allow the greatest degree of accuracy, however, may not be the same as those required for greatest degree of speed of work. Management must assist in the determination of the most critical criteria.

Good functional vision can be achieved in most cases with professional eye care. Abundant evidence supports the concept that visual functions are important factors in safety. The provision of appropriate eye care can allow most employees to meet visual standards, and a reduction of accidents may result.

TYPES OF RELATION.

It has been demonstrated on many different jobs that employees who have been classified according to their job proficiency do differ with respect to certain visual skills. Those who do the job best usually have certain visual characteristics that are not found as frequently, or to the same degree, among those who do not do it as well.

PATTERNS OF VISUAL REQUIREMENTS.

Each test in the battery of vision tests is separately analyzed in relation to job success. Some of the tests may show a relation to success on a particular job, others may not. On each related test, a range of scores is designated as optimum for the job. The total pattern of these visual requirements represents the pattern of visual skills that is predictive of success on this job. Such a pattern, or profile, of visual requirements for close work is illustrated in Figure 6.

Vision and Successful Job Performance

There are many qualities of the worker's performance on the job that contribute to the degree of job success.⁵⁶

PRODUCTION.

The elements that make up production are measurable as number of pieces produced, earnings, and waste or rejects and in ratings given by supervisors.⁵³ “Different visual characteristics will vary in their relative importance on different small assembly operations; and on any one operation, visual characteristics will vary in importance with respect to different industrial criteria, such as quantity and quality of work.”²⁶

TURNOVER.

A further difficulty often encountered by industrial management is the problem of labor turnover. Much needless expense is incurred in the training of new employees who, after such training, remain on the job only a short time. The elimination of these applicants who have a low predictability of success can reduce the problem. Visual testing plays a role in this success.

DEFINITION OF “NORMALS” FOR JOB

The Joint Industrial Ophthalmology Committee (1944) published the following definition of normals for job²¹

1. Acuity—In considering job classification “Normal” is of two varieties, the “clinical” or standard (theoretical) normal, and the “job normal.” The latter makes it possible for a person whose vision deviates from the perfect acuity standard to qualify for certain jobs. The term, “substandard,” is often used instead of “defective.”
   
2. Stereopsis—There is no generally accepted percentage standard although Dr. Marshall Parks considers 40 seconds or better as representing bifoveal fixation and 60 seconds or worse representing extrafoveal fixation.
   
3. Color Perception—This should be recorded by pseudoisochromatic plates and interpreted on the basis of the job requirement.
   
4. Muscle Balance—Arbitrary standards of not more than 3 degrees (6 prism diopters) of esophoria and 5 degrees (10 prism diopters) of exophoria for distance, and 2 degrees (4 prism diopters) of esophoria and 8 degrees (16 prism diopters) of exophoria for near, are used as a matter of recording normal or substandard.
   
5. The Functional Normal—The occupational (industrial) ophthalmologist should recognize the fact that a clinically normal pair of eyes—that is, normal according to the usual standards, may be abnormal for some specific job, or inadequate to abnormal work demands. By way of example, 8 inches is a normal work distance. Clinically normal eyes might not be able to function normally at that distance but with certain occupational lens additions could be made to function at this distance.
   

OTHER IMPORTANT FACTORS

Other important factors that may need to be considered include:

1. Dark adaptation—important for truck drivers, night flyers, soldiers, welders, and so forth.
   
2. Form field—important in aviation and as a safety factor, and so forth.
   
3. External gross pathologic condition—toxic gases, and so forth.
   
4. Admission or survey examinations revealing very low vision require further study to determine the possibility of a serious pathologic condition. For example, congenital amblyopia or an optic atrophy existing from childhood may later be made the basis for an industrial compensation claim and should be recorded as existing before employment.
   
5. More detailed knowledge of close visual function—this becomes necessary as one understands occupations in which the near point of accommodation and ductions play an important part in efficiency. The condition of near vision should be carefully measured and recorded in the initial eye testing.
   

REFRACTIVE ERRORS

Refractive errors are always important. Suitable arrangements for refractive examinations must be made. These needs will vary with size of plant and with location. It is important for the physician to know which visual defects are of importance to job success and which may require correction. Not all defects are incapacitating, and some may not require treatment. It is important to prevent applicants slipping through admission evaluations without detection of visual defects.

PURDUE VISUAL STANDARDS

The Purdue group studied those vision tests whose relationship with job efficiency has been investigated and have proved to be most useful.^23,26,56 Not only are relationships between individual tests and job performance important but the pattern of visual skills revealed by a combination of these 12 tests is also important. This pattern, or “profile” as it is called, discloses an additional relationship to job performance.

The establishment of visual standards on a factual or statistical basis is essentially one of establishing individual differences in job performances and individual differences in visual skills, determining how differences in job performances are dependent on differences in visual skills, and then determining how these differences in job performance may be predicted, to some extent, on the basis of the visual skill test. Questions to be answered include

1. What vision tests are related to specific measures of performance on a specific job and are the results reproducible?
   
2. What degree of performance on these tests is requisite for average performance on a job, and what degree is desirable for maximum performance?
   
3. What difference in average job performance for the group as a whole could be expected if all workers on the job had the requisite or desirable visual skills?
   

There are jobs so highly specialized that they never fall into any one group. The minimum visual standards for each of these jobs must be established clinically by the observation and visual ergonomic methods. The investigation of specialized jobs is not only necessary but is an intensely interesting and often a thrilling experience. Constant and continued study of visual job demands on visual capacities is the primary dictum to all parties concerned.

Visual profiles and minimum visual standards are outlined in Figure 6. Although the Ortho-Rater was the testing instrument, it can actually be used with any reliable battery instrument (e.g., Titmus and Stereo Optical current models) or with individual tests on the basis of the clinical equivalents. The unique and exhaustive research contribution, on which the whole structure of fact-finding techniques and basic evaluation of visual skills has been laid, can now be the broad basis for professional thinking in visual skills (physical capacities) as matched to visual demands.

It is also important to differentiate between visual standards for hiring—which vary often, according to state law—and placement standards. This chapter discusses the latter.

Kephart⁵⁵ discussed methods in which the relationship between each of the 12 tests and performance on the job was investigated to determine the pattern of visual skills required by a job. When comparisons have been made on the basis of the individual tests, the results are pooled and the resulting pattern of visual skills is expressed as a battery of tests with varying cut-off scores. Not all jobs require the same pattern of visual skills. The job profiles, published in countless reports, are the result of careful and long-continued research involving large numbers of workers in a large variety of jobs. Such patterns must always be arrived at by a careful observation of large numbers of statistically demonstrated relationships between test scores and job success.

VISUAL JOB FAMILIES

Tiffin²⁶ has shown that jobs differ both in the types of visual skills they demand and in the quantity of these visual skills required of the worker. Just as there are differences between types of jobs, however, there are also similarities. As we noted differences in visual activities between such jobs as crane operator and radio assembler, there are observed similarities in visual activities between jobs, such as lathe operator and milling machine operator. Similarities between visual requirements of jobs are as important as differences between jobs.

Over a number of years, the Purdue University Occupational Research Center²⁶ has collected data involving visual test scores and measures of job success for several thousand different industrial jobs. A careful analysis of the relationships between vision test scores and job success has shown that there are certain groups of jobs that are similar to each other in visual requirements. Within each group the visual requirements of the jobs are similar, but the requirements of each group vary from those of the next group. Thus, we have a series of job groupings that represent a different pattern of visual requirements, although the jobs within each group are essentially similar in visual requirements. This has led to the concept of visual job families. A visual job family is composed of a group of jobs whose visual requirements are similar.²⁶ The requirements between families, however, differ.

In the early development of industrial ophthalmology, six visual job families were identified.^23,26,56 It is felt that most industrial jobs will fall into one of these six groups in the visual demands the job makes on the worker. The visual requirements of Bausch & Lomb Ortho-Rater test scores of each of the six job families are given in Figure 6.²³ These findings are provided in Tables 2, 3, 4, 5, 6, and 7 as Column A. Kuhn, based on her extensive experience (1935 to 1950), devised minimum visual standards for use by medical directors and consultants. They are the same main groups, but they are expressed in clinical terms and differ occasionally (listed in Tables 2, 3, 4, 5, 6, and 7 as Column B). The profile and group numbers in Tiffin,²⁶ Kuhn,²³ and Novak⁵⁶ do not agree but the family names do, and, therefore, they have only been used in Tables 2, 3, 4, 5, 6, and 7. (It is important always to remember that these are minimum requirements.) The sketches are presented with the knowledge that they are not complete descriptions of the groups (Tiffin,²⁶ Kuhn,²³ and Novak⁵⁶).

TABLE 2. Visual Job Family—Clerical and Administrative Profile

TABLE 3. Visual Job Family—Inspection and Close Machine Work Profile

TABLE 4. Visual Job Family—Operator of Mobile Equipment Profile

TABLE 5. Visual Job Family—Machine Operators Profile

TABLE 6. Visual Job Family—Laborers Profile

TABLE 7. Visual Job Family—Mechanics and Skilled Tradesmen Profile

ELEMENTS OF VISUAL (OCULAR) FUNCTIONS

Visual (or ocular) function requirements are important to the safety, health, and efficiency of industrial workers. Vision is essential for nearly all occupations. It is most important in the identification of distant objects and for detailed perception of shape and color. Visual senses allow judgment of distance and gauging of movements in the visual field. To provide good eye care, a practitioner must understand an individual's activities in the home, farm, school, or at the workplace and the associated hazards.^41,42 The Joint Industrial Ophthalmology Committee²¹ has established the following elements of visual (now called ocular) function requirements:

1. Acuity.
   Monocular and binocular.
   Distance and near.
   With and without correction.
   
2. Stereopsis—Testing techniques for stereopsis in a binocular instrument have been greatly improved. Permanent test records enables one to note changes in stereopsis.
   
3. Color perception is important in most industries. The identification of red, green, blue, yellow hues will be job specific generally. It is important to recognize that color deficiencies will interfere with safety and efficiency of various tasks.
   
4. Muscle balance (distance and near) is a common term chosen to present the concept of binocular balance to the layman. The examination of muscle function includes tests for vertical and horizontal phorias.
   1. General limits of normal functional balance are established for both far and near vision.
      
   2. Determination of adequate balance for an individual's comfort, efficiency, and safety is determined by the specific occupation. No absolutes are possible but the degree of interference with comfort is an index that can be used to determine the need for correction.
      
   
   

Visual screening was defined by a conjoint proposal from the American Academy of Pediatrics, the AAO, the Eye and Vision Committee of the ACOEM, and the American Academy of Pediatric Ophthalmology and Strabismology.^57,58

• The key element is determination of screening visual acuity, both quantitative and bilateral.
  
• Graduated visual acuity stimuli should be employed to allow quantitative determination of visual acuity (e.g., Snellen chart).
  
• Screening may include determination of contrast sensitivity, ocular alignment, color vision, and visual fields.
  

There was no procedural terminology code at that time.

VISUAL SCREENING TESTS

Battery Tests

Typical Snellen charts represent only one measurement of the ability of the eyes to discriminate black and white detail at some standard distance (central visual acuity). Often, the distance at which the work must be performed is not considered when performing and evaluating these tests. The significance of any single test depends on the job requirements. Specific individual correlation between the visual demands of the job and the visual qualifications of the applicant should be applied. A visual history questionnaire specific for visual screening is useful (Fig. 7).

Vision is a complex act, requiring individual excellence, as well as many coordinated functions in which both eyes must work in unison. To understand the need for testing several visual skills in an industrial eye examination, it would be well to review the functions of the eye.

Careful diagnostic appraisal of near vision (near point acuity, near point accommodation, near point of convergence, lateral and vertical phorias, and others) (see Fig. 5) is important for job applicants requiring exact visual perception at working distances of 16 in. or less. This is especially true for employees older than 40 years. Other desirable information may be of assistance in determining an employee's visual skill, but it is not often readily available in industry. An estimate of intraocular tension and ophthalmoscope findings are related more specifically to health rather than to eye efficiency. In some jobs, speed of vision and recovery from glare may be important. The significance of any single one of the previous tests depends entirely on that particular job. There must be specific individual correlation between the visual demands of the job and the visual qualifications of the applicant.

Necessary data can be secured by standard individual tests, but these can be time consuming and require commitment of considerable space. In recent years, binocular testing instruments have been used by industry to discover visual defects and appraise visual skills. Such equipment is portable, durable, and has been designed to optimize accuracy and speed. A test battery should be regarded as a screening test, to detect substandard visual qualifications. Results do not provide diagnoses, and follow-up procedures may be necessary. Employees who exhibit a high standard of visual performance for a specific job can be certified. Employees who appear to have limitations of visual skills that are likely to affect their work should be referred to a competent professional who has knowledge of the visual requirements of the various job classifications in the plant or who is specifically informed as to the type of job for which the employee is being considered.

The employee should be informed of any need for visual assistance to perform his or her job. In turn, the professional consultant should report the findings to the plant medical department if corrective lenses are prescribed. This should include comment on the vision with prescribed lenses, the intended use (for distance vision, near vision, or for some specific working distance), and any need for follow-up appointments.

Techniques of Testing²¹

In 1944, the Joint Industrial Ophthalmology Committee defined factors that should influence the selection of a technique including

1. The environment within industry and the need for accurate first screening methods.
   
2. The time required for an accurate unit examination (i.e., 3 to 5 minutes)
   
3. The need for simplicity of battery tests—intelligence of the employee that has to be considered and safeguards established to prevent mistakes.
   
4. The need for standardized conditions of testing—ideally achieved when using a single instrument for the basic battery and adding special tests as needed for specific occupations.
   
5. The need for practical methods of record keeping at time of examination.
   
6. The need for well-trained personnel, ideally under medical control.
   

A practical technique, considering the factors mentioned previously, consists of a single sequence of binocular battery of tests including all basic elements of visual performance and additional tests for specialized needs as desired.

Current Testing Methods²⁷

Most visual tests required may be provided by use of visual screeners. Currently, the following instruments are available.

TITMUS MODEL 2A SCREENER (TITMUS OPTICAL, INC., PETERSBURG, VA).

1. Binocularity.
   
2. Visual acuity, distant, intermediate (VA. D, INT.) (20 to 40 in.) near: monocular and binocular.
   
3. Color vision red or green.
   
4. Muscle balance—heterophoria or heterotropia, horizontal and vertical.
   
5. Stereopsis.
   
6. Peripheral vision—horizontal plane.
   

THE TITMUS 2C VISION SCREENING SYSTEM (TITMUS OPTICAL, INC., PETERSBURG, VA).

The Titmus 2c Vision Screening System is the computerized vision screening system for the occupational model only. The computerized vision screening system consists of a model 2a Vision Screener, an encoder (interface device between a computer and vision screener) and the Optimum for Windows software. The features of the software include

1. Binocularity.
   
2. Controls vision screener from computer.
   
3. Eliminates manual scoring using record forms.
   
4. Records test results on the computer screen.
   
5. Compares and interprets test results to preset or customized job standards.
   
6. Prints test results—Interpretation Report.
   
7. Exports test results in ASCII format.
   

STEREO OPTICAL MODEL OPTEC 2000C VISION TESTS (STEREO OPTICAL CO., INC., CHICAGO, IL).

1. VA. D, INT. (20 to 36 in) near: monocular and binocular.
   
2. Color vision red or green.
   
3. Muscle balance—heterophoria or heterotropia, horizontal and vertical.
   
4. Stereopsis.
   
5. Peripheral vision—horizontal plane.
   
6. Contrast sensitivity available.
   

THE NEW MODEL OPTEC 3500 VISION TESTING SYSTEM.

In addition to the features of Models 2000 and 2500, it includes

1. Target illumination for day and night testing.
   
2. Glare illuminance at distance for day and night testing.
   
3. Contrast sensitivity.
   
4. Potential acuity (assessment macular functions in cataract patients).
   

The Department of Defense uses an armed forces visual screener—Bausch & Lomb Ortho-Rater manufactured to specifications by Stereo Optical Company (Chicago, IL) Armed Forces tester Model 2300 AFUT Vision Tester. Other instruments currently in use but not being manufactured at the present time include Bausch & Lomb and American Optical instruments previously described. The tests may be provided through individual separate instruments.

In specific types of occupational testing, for example, Department of Transportation (DOT), Federal Aviation Administration (FAA), Federal Railroad Administration (FRA), and maritime industry, as well as the military, the Farnsworth Lantern (now Stereo Optical Co. Model 900) is required when the individual fails the Ishihara color screening plates.

EYE EXAMINATIONS FOR ENVIRONMENTAL AND MEDICAL SURVEILLANCE

Environmental health programs may involve activities designed to ensure that employees, customers, and the public are adequately protected from health hazards associated with a company's operations.⁵⁹ Hazards may include conditions, other than indoor air contaminants, that cause stress, discomfort, or health problems. Environmental monitoring provides for the systematic collection, analysis, and evaluation of environmental samples, such as air, to determine contaminant levels to which workers are exposed.

Medical surveillance programs may include detailed physical examinations to recognize a specific effect.⁵⁹ Some environmental hazards may be associated with changes in visual functions resulting in abnormalities on screening. Solvent exposure, for example, has been associated with changes in the retina and optic nerve resulting in an acquired change in decreased contrast sensitivity and acquired color vision defects, starting first with yellow-blue and proceeding to red-green. Current work at Environmental Protection (EPA) is evaluating contrast sensitivity in neurotoxicity.

1. Visual screening history. A general overview of the individual's visual history is required (Fig. 7).
   
2. Complete visual (ocular) screening examinations.
   1. Visual acuity quantitative bilateral tests measured at infinity (as a minimum and especially in pediatrics), near and intermediate distances (based on job description), contrast sensitivity done periodically, all performed with and without corrective devices (glasses, contact lenses).
      
   2. Color vision.
      
   3. Gross visual fields.
      
   4. Heterophoria/heterotropia (horizontal and vertical) and depth perception.
      
   5. Intraocular tensions (e.g., puff tonometer).
      
   
   
3. Counseling participatory guidelines—Risk factor reductions. Interpretation of findings against standards (Purdue, FAA, Federal Highway Transportation Agency [FHTA], DOT, Department of Energy [DOE], etc.), counseling, anticipatory guidance/risk factor reduction interventions.
   
4. Ordering of appropriate laboratory/diagnostic procedures followed by referral to an appropriate eye specialist, depending on the defect, when an individual fails to meet standards.
   
5. A written summary of the case.
   

PERFORMANCE OF ESSENTIAL FUNCTIONS WITH OR WITHOUT ACCOMADIATION

The ADA of 1990,²⁸ as implemented in most facilities in July of 1992 under Title 1 on employability, requires that the individual must be able to perform the essential functions of the position with or without accommodation (e.g., acquisition or modifications of equipment or devices and appropriate adjuvant or modifications of examinations, training methods, or policies) without substantial risk or direct threat to himself or herself and to others. Many federal agencies have published visual standards, and industry must carefully consider any contradictions between regulatory requirements and the ADA guidelines. The June 1999 Supreme Court opinion provides some recent legal guidance.^27,61,62 In presentations to the AAO and at the American Occupational Health Conference, Blais discussed the relevancy of visual requirements to efficiency and safety.^27,41,42 These workplace requirements are no different from what one would expect and desire from anticipating to drive a car, play sports, do hobbies, or perform hazardous duties at school or on the farm.

The federal laws most relevant to a decision regarding vision standards for applicants include the Rehabilitation Act of 1973⁶¹ and the ADA of 1990.²⁸ The Rehabilitation Act makes it unlawful for an employer who receives federal financial assistance to exclude, or otherwise discriminate against, persons solely because of a handicap. The presence of a handicapping condition is not a permissible ground for assuming a person is unable to function effectively in a particular job. Handicapped individuals who meet all the employment criteria except for the challenged discriminatory criterion and who can perform the essential functions of the job with or without reasonable accommodations cannot be rejected from a job simply because of a handicap. The critical issue in the determination of vision standards for recruits is whether people with certain levels of visual impairment are able to perform the essential functions of the job with or without accommodations.

The determination of whether an individual with a disability is qualified to perform a particular job is to be made at the time of the employment decision. Such a determination should not be based on speculation that the employee may become unable in the future or may cause increased health insurance premiums or workers' compensation costs.⁶¹ A recent U.S. District Court decision⁶² required a formal medical panel report to evaluate, and make binding, a definition of certain visual standards to be used for Philadelphia police recruits that clearly addresses the legal requirements for employment under ADA for job classifications.^28,62

ESSENTIAL FUNCTIONS OF THE JOB^28,62

The “essential functions” of a particular job as defined in the Rehabilitation Act⁶² and ADA of 1990²⁸ may be determined using the job description formulated by the employer or by relying on those familiar with the particular job. Not all job functions articulated by an employer are essential functions nor are all employer qualifications to be accepted as essential. Although legitimate physical qualifications may be essential to the performance of certain jobs, such a determination must come from careful scrutiny of the evidence. Available accommodations to overcome physical limitations must be considered. An employer's justification for excluding a person based on a disability must be grounded in a careful, open-minded consideration of the risks and alternatives and not by simple conclusory statements used to justify reflexive reactions grounded in ignorance or prejudice.

REASONABLE ACCOMODATION—DEFINED IN KIMBLE V. HAYES ET AL.^28,62

If a handicapped person is unable to meet the employer's requirements, it is the employer's obligation to investigate and determine whether a reasonable accommodation can be made to enable the person to perform the job. Reasonable accommodations may include but are not limited to acquisition or modifications of equipment or devices and appropriate adjustment or modifications of examinations, training materials, or policies. In a vision case, some accommodations proposed in the record include polycarbonate lenses, contact lenses, and eyeglass straps. If reasonable accommodations do exist, these must be used rather than excluding the handicapped person. Otherwise, the employer is required to demonstrate factually on the record that making reasonable accommodations would either require a modification of the essential nature of the job or impose an undue burden on the employer. A reasonable accommodation may require an employer to accept minor inconvenience or to bear more than an insignificant economic cost in making allowance for an applicant's handicap.

An employer may require, as a qualification standard, that an individual not pose a direct threat to the health or safety of himself or herself or others. The determination that an individual with a disability poses a direct threat should be made on an individual case-by-case basis. The determination may also be based on a reasonable medical judgment that relies on the most current medical knowledge and/or on the best available objective evidence. In determining whether an individual would pose a direct threat, the factors to be considered include the duration of the risk, the nature and severity of the potential harm, and the likelihood that the potential harm will occur.

The law requires that consideration must rely on objective factual evidence—not on subjective perceptions, irrational fears, patronizing attitudes, or stereotypes—about the nature or effect of a particular disability or of disability generally. Relevant evidence may include input from individuals with the disability, experiences of individuals with the disability in similar positions, and opinions of medical doctors or others who have expertise about the disability involved or who have direct knowledge of individuals with the disability.

If an individual poses a direct threat as a result of a disability, the employer must determine whether a reasonable accommodation would either eliminate the risk or reduce it to an acceptable level. An employer is not permitted to deny employment to an individual with a disability merely because of a slightly increased risk. The risk can only be considered when it poses a significant risk. A significant risk is a risk that has a high probability of substantial harm. A speculative or remote risk is insufficient to exclude someone from employment.

BURDEN OF PROOF—PREPONDERANCE OF THE EVIDENCE^28,62

Before an employer can exclude an individual with a handicap, the employer must meet its burden of demonstrating by a preponderance of the evidence that the handicapped individual cannot perform a job with or without reasonable accommodations. Handicapped people should be eligible for employment unless they cannot perform the job with or without reasonable accommodation. Preponderance of evidence means the greater weight of the evidence. It refers to the quality and persuasiveness of the evidence, not to the number of witnesses or documents. So long as the scales tip, however slightly, in favor of the party with this burden of proof—that what the party claims is more likely true than not true—then it will have been proved by a preponderance of evidence.

The Rehabilitation Act of 1973 prohibits discrimination against people with handicaps by employers who receive federal financial assistance. The ADA was modeled after the Rehabilitation Act of 1973. Essentially, it extends the provisions against discrimination to private employers. It prohibits discrimination against people with disabilities by private employers whether or not they receive federal financial assistance. The ADA also is more explicit and detailed about the extent that employers must go to include people with disabilities in their workforce and what is meant by reasonable accommodations.

IMPAIRMENT

Impairment is “a loss of use, or derangement of any body part, organ system, or organ function.” The purpose is to provide the physician with criteria for evaluating permanent impairments of the visual system as they affect an individual's ability to perform ADLs. This revision is based on a consensus of the International Society for Low Vision Research and Rehabilitation, and was published in the Guide for the Evaluation of Visual Impairment.⁶⁴

A medical impairment can develop from an illness or injury. An impairment is considered permanent when it has reached maximal medical improvement (MMI), meaning it is well stabilized and unlikely to change substantially in the next year with or without medical treatment.⁶⁵

DISABILITY

The term disability has historically referred to a broad category of individuals with diverse limitations in the ability to meet social or occupational demands. However, it is more accurate to refer to the specific activity or role the disabled individual is unable to perform. Several organizations are moving away from the term disability and instead are referring to specific activity limitations to encourage an emphasis on the specific activities the individual can perform and to identify how the environment can be altered to enable the individual to perform the activities associated with various social or occupational roles.⁶⁶

According to a 1997 Institute of Medicine Report, “disability is a relational outcome, reflecting the individual's capacity to perform a specific task or activity, contingent on the environmental conditions in which they are to be performed.” Disability is context-specific, not inherent in the individual, but a function of the interaction of the individual and the environment.⁶⁷

The World Health Organization (WHO) is revising its 1980 International Classification of Impairments, Disabilities and Handicaps⁶⁸ and has released a draft document, The International Classifications of Impairments, Activities and Participation (ICIDH-2).⁶⁹ The term disability has been replaced by a neutral term, activity, and limits in ability are described as activity limitations. The Guides continues to define disability as an alteration of an individual's capacity to meet personal, social, or occupational demands or statutory or regulatory requirements because of an impairment.⁶⁰ An individual can have a disability in performing a specific work activity but not have a disability in any other social role. Physicians have the education and training to evaluate a person's health status and determine the presence or absence of an impairment. If the physician has the expertise and is well acquainted with the individual's activities and needs, the physician may also express an opinion about the presence or absence of a specific disability. For example, an occupational medicine physician who understands the job visual requirements (essential functions) in a particular workplace can provide insights on how the impairment could contribute to a workplace disability.

The US Supreme Court in the case Toyota Manufacturing, Kentucky Inc. Petitioner v Ella Williams⁷⁰ said the following:

Under the Americans with Disabilities Act of 1990 (ADA or Act), 104 Stat. 328, 42 U.S.C. §12101 et seq. (1994 ed. and Supp. V), a physical impairment that “substantially limits one or more… major life activities” is a “disability.”

Disability exists if a person has an impairment that substantially limits one or more of life's activities, has record of such impairment, or is regarded as having such an impairment.^60,63

“Substantially limits one or more major life activities”⁶³ includes the following three factors: (1) its nature and severity, (2) how long it will last or is expected to last, and (3) its permanent or long-term impact, or expected impact. The individual is unable to perform or is significantly limited in the ability to perform an activity compared with an average person in the general population. Examples of “major life activities,”⁵ as defined by the Equal Employment Opportunity Commission Technical Manual, Title 1, are walking, seeing, speaking, hearing, breathing, learning, performing manual tasks, caring for oneself, and working. Other activities may include sitting, flying, standing, or reading.⁷¹

A “handicapped and disabled individual,” according to the AMA, is an impaired individual not able to accomplish a specific task or activity despite accommodation, or if no accommodation exists that will enable completion of the tasks (e.g., not allowed to wear contact lenses in work environment).

The impairment evaluation, however, is only one aspect of disability determination. A disability determination also includes, information about the individual's skills, education, job history, adaptability, age, and environment requirements and modifications. Assessing these factors can provide a more realistic picture of the effects of the impairment on the ability to perform complex work and social activities. If adaptations (minimal accommodations) can be made to the environment, the individual may not be disabled from performing that activity.⁶⁵

Medical impairments are not related to disability in a linear fashion. An individual with a medical impairment can have no disability for some occupations, yet be very disabled for others. A pilot who develops a visual impairment, correctable with glasses, may be able to perform all of his daily activities but is no longer able to fly a commercial plane.⁶⁵ The Guides is not intended to be used for direct estimates of work disability. Impairment percentages derived according to the Guides criteria do not measure work disability. Therefore, it is inappropriate to use the Guides' criteria or ratings to make direct estimates of work disability.⁶⁵

The individual must be able to perform the essential ocular functions with or without accommodations without substantial risk or direct threat to themselves and to others.

HANDICAP

Handicap is a term historically used in both a legal and a policy context to describe disability or people living with disabilities. Thought the term continues to be used, generally it is being replaced with the preferred term disability.⁶⁵

TABLE 8. Aspects of Vision Loss

In evaluating impairment, the Guides considers both anatomic and functional loss. Some chapters place a greater emphasis on either anatomic or functional loss, depending on common practice in that specialty. Anatomic loss refers to a change in function for the organ or body system.⁶⁵

Loss, loss of use, or derangement implies a change from a normal or preexisting state. Normal is a range or zone representing healthy functioning and varies with age, gender, and other factors such as environmental conditions. For example, normal heart rate varies between a child and adult and according to whether the person is at rest or exercising. Multiple factors need to be considered when assessing whether the person is at rest or exercising. Multiple factors need to be considered when assessing whether a specific or overall function is normal. A normal value can be defined from an individual or population perspective.⁶³

ANATOMICAL AND STRUCTURAL CHANGES

This aspect describes the underlying disorders or diseases at the organ level. Ophthalmoscopy and slit lamp biomicroscopy have given ophthalmology tools to describe anatomical changes in more detail than is possible for many other organ systems. Most of the ophthalmic literature is devoted to this aspect, yet these changes give us relatively poor cues to the severity of their functional consequences.⁷²

VISUAL FUNCTIONS

Visual functions are measured quantitatively (e.g., visual acuity). This aspect describes functional ocular changes at the organ level. Here again, ophthalmology has developed unique tools that can measure visual functions, such as visual acuity and visual field, in great detail. These tools are well developed and give objective measurements.⁷² These measurements can be used for two purposes: to assist in diagnosing the underlying disorder or to predict the functional consequences (Table 9). For example, tests such as electro retinography (ERG) and visual eye potential (VEP) are helpful in diagnosing the underlying condition, but are poor predictors of the functional consequences. Because visual acuity loss can have many different causes, visual acuity testing adds little to the differential diagnosis, but can help in predicting the impact on ADLs. The Ishihara color test is good at diagnosing even minor red-green deficiencies but overestimates the functional consequences. The D15 color test on the other hand was designed to be insensitive to minor deficiencies and to detect only those that might have functional consequences. The discussion will be oriented toward the functional consequences.

FUNCTIONAL VISION

Functional vision is described qualitatively (e.g., reading ability). This aspect reaches beyond the description of organ function by describing the skills and abilities of the individual. It describes how well the individual is able to perform ADLs excluding work, given the vision loss. This aspect has been described under different names. In the field of vision, the term functional vision is used. In ICIDH-80 loss (or lack) of ability was described as dis-ability.⁶⁸ Its successor, ICIDH-2 provides a taxonomy of activities and of the ability to perform them.⁶⁹ The use of the term disability is discouraged because it may have different meanings in different contexts. (Having a disability may be a synonym for having an impairment; being disabled points to a loss of ability; being on disability points to an economic consequence.) In the AMA Guide to the Evaluation of Permanent Impairment the term impairment refers to organ function, impairment rating refers to an estimate of the ability to perform ADLs excluding work.⁶⁵

SOCIETAL AND ECONOMIC CONSEQUENCES

The last aspect describes the societal and economic consequences for the individual caused by an impairment or by a loss of ability. In ICIDH-80 this aspect was described as handicap and measured in terms of loss of independence⁶⁸; in ICIDH-2 it is described under the heading participation plus performance and vision related to quality of life. Handicaps do not preclude participation.⁶⁹ The story of Helen Keller is one example of how some people can achieve full participation in spite of extraordinary handicaps.

The first two aspects refer to the organ system. The other two refer to the individual (see Table 8). The first aspect is that of anatomical and structural change.^63,72 Defects are described as disorders (diseases or injuries). The second aspect is that of functional changes at the organ level; examples are visual acuity loss and visual field loss. Defects are described as impairments. The next two aspects refer to the individual. One aspect describes the generic skills and abilities of the individual. The other aspect describes the skills and abilities of the individual. Defects are described as ability loss (disabilities). The last aspect points to the social and economic consequences of a loss of abilities and are described as handicaps and as a lack of participation.

IMPAIRMENT VERSUS DISABILITY EVALUATIONS

An impairment versus disability evaluation is quite difficult for a medical records reviewer (as an independent medical examiner to provide hands-off evaluation of a patient), who must make judgments regarding disability when the actual permanent impairment had not been objectively determined and the individual certified as impaired.^60,64,65 An impairment is not synonymous with a disability. Impairment is a measurable detriment in health status evaluated by medical means. A disability is assessed by the consideration of nonmedical issues such as the person's education, vocational skills, experience, and age.

The evaluating physician (sometimes the treating physician) is often asked to conduct an impairment evaluation as part of his or her assessment. An impairment evaluation is not synonymous with a disability evaluation. The (AMA) Guides to the Evaluation of Permanent Impairment clearly distinguishes the terms impairment and disability. The impairment is a functional change at the organ level while a disability is a change in the skills and ability of the individual (Table 8).

The purpose of the AMA Guide (5th edition)⁶³ is to provide a reference framework; achieve objective, fair, and reproducible evaluations; minimize adversarial situations; and provide a process for collecting, recording, and communicating information.

PROBLEMS: RATING IMPAIRMENTS THAT ARE PERMANENT

The EEOC guide applies only to “permanent impairments.”^28,60,63 The impairment that has become finalized is unlikely to change despite further medical or surgical therapy or is unlikely to change substantially by more than 3% within the next year with or without medical treatment. It is anticipated that the maximum medical improvement has been reached based on the evidence that it is stable and plateaued, permanent, and stationary. This does not preclude follow-ups, maintenance or palliative care, and a 3% change over time. The problem arises when there is inappropriate use of an impairment number and when one does not provide additional clinical information and does not provide information concerning disability. An additional area of confusion relates to the “whole person” concept in which all physical and mental impairments affect the whole person and all ratings are “combined.” All physical and mental impairments affect the whole person, and as a result all impairment ratings are combined. “A method of combining impairments is based on the idea that a second or succeeding impairment should apply not to the whole, but only to the part that remains after the first and other impairments have been applied.”^63,65

In cases of inconsistencies of measurements, the impairments must be based on objective findings. Despite observations or test results, medical evidence appears to be a sufficient way to verify that a permanent disability of a certain magnitude exists. The physician should modify the impairment, describing the modification and explaining the reason for it in writing.

In interpolating, measuring, and rounding off, the readings should lie within 10% of each other. Separate evaluators should lie within 10% of one another, and range of motion measurements are rounded to the nearest 10 degrees. The final estimate may be rounded off to the nearest zero or 5%.

Although this information involves all systems of the body, in my opinion, it is critical that, before one starts looking at a visual disability of a patient, one must first make several decisions. Does the patient have an impairment? Is the impairment permanent or temporary? If temporary, how long will it last? To evaluate a permanent impairment of the eyes, according to the AMA guide, a given amount of specific data must be obtained.

The AMA Guide to Evaluation of Permanent Impairment remains the major reference for determinations of impairment to any body systems. The 5th edition⁶³ chapter on “Functional Impairment of the Visual System” has been significantly revised from the 4th edition.⁶⁰ The impairment ratings in this chapter provide an estimate of the severity of the effects of certain types of visual loss on the ability to perform activities of daily living (ADL).⁶³ This revision is based on a consensus of the International Society for Low Vision Research and Rehabilitation and was published in the Guide for the Evaluation of Visual Impairment.⁶⁴

A NEW STANDARDIZED CLASSIFICATION OF OCULAR TRAUMA (BIRMINGHAM EYE TRAUMA TERMINOLOGY (BETT)

A new classification⁷³ has been endorsed by the AAO, Board of Directors of the International Society of Ocular Trauma, United States Eye Injury Registry, the Hungarian Eye Injury Registry, the Vitreous Society, the World Eye Injury Registry and the Retina Society (Fig. 8). When the system was published in 1996, it was reasonably expected that the system eventually will become the standardized international language of ocular trauma. Ophthalmologists were urged to use this terminology in clinical practice and research.⁷⁴ It is mandated by Graefes Archives, Klinische Monatsblätter, and Ophthalmology. Definitions in medical dictionaries are tailored toward general medical use and cannot be effectively applied to ocular trauma. The new system always uses the entire globe as the tissue of reference; therefore, the type of the injury is described unambiguously without the need to indicate the tissue involved. When a tissue is specified, it refers to wound location not to injury type. A corneal penetrating injury, thus, involves an open globe injury with the wound being in the cornea. The system provides unambiguous definitions for each term (Table 10) and a complete classification of injury types.

TABLE 10. Birmingham Eye Trauma Terminology (BETT) Glossary of Terms

Elements of the History of Ocular Injury

It is important to obtain a detailed history of an ocular injury. Such information may be obtained from a variety of sources, including the patient, first responders, or others involved or associated with the accident. Information should include the 4 w's (where, when, who, and what), that is, the site of accident, the time and date, the individuals involved, and a detailed description of the circumstances. If chemical exposure was involved, available material safety data sheet (MSDS) information should be sought. Critical data includes^75,76

1. Type of chemical—alkali, acid, solvent.
   
2. Volume of spillage.
   
3. The pH of the material.
   
4. The concentration of the material.
   
5. The solubility of the material.
   
6. The contact time.
   
7. Emergency medical care by the first responders.
   
8. Product manufacturer.
   
9. Availability of chemical data.
   • MSDS.
     
   • Regional poison control center.
     
   • Internet.
     
   
   

Yardsticks that can be used to evaluate standard emergency care include

1. The detail and accuracy of the history obtained at the time of, or subsequent to, admission.
   
2. The thoroughness of the admission examination.
   
3. The correlation of critical results with medication and/or other treatment provided to the patient.
   

Ocular Examination of Injury to the Eye⁷⁷

The examination of the injured eye should include

1. Visual acuity (each eye separately)—with best correction or pinhole done prior to further examination or treatment except for chemical injury where the procedures are reversed.
   
2. Inspection of the ocular structure—if laceration of globe suspected no pressure should be exerted on the globe.
   
3. Position of the eyes and eye movements (six cardinal positions).
   
4. Examination of the pupils for size and reaction to light.
   
5. Gross visual fields—by confrontation.
   
6. Ophthalmoscopy.
   
7. Intraocular pressure (IOP), if acute glaucoma is suspected.
   

It is important that the primary care physician make an immediate referral to the closest ophthalmologist or eye institute when eye injuries are beyond his or her capability. See the occupational medicine practice guidelines on evaluation and management of common health problems and functional recovery in workers. The patient should be made comfortable (with intravenous analgesics, if necessary), and the injured eye protected from further injury by application of a Fox shield or equivalent and a patch over the other eye in cases of an open globe. Depending on the type of injury, the patient should be transported on a stretcher.

PREVENTION

General Principles

The ACOEM guidelines provides the following guidelines⁷²: Prevention of work-related health complaints should be a top priority for occupational health professionals. Diagnosis and treatment of workers with work-related problems offers an opportunity to prevent recurrences (tertiary prevention), to mitigate the effects of existing work-related hazards to reduce the duration of the problem (secondary prevention), and to prevent similar problems in coworkers and those in similar jobs (primary prevention). Various levels of certainty regarding causation and differences in the severity of adverse effects may justify degrees of response. Interventions may prevent recurrences and hasten recovery if significant factors are identified. Musculoskeletal, psychologic, or other problems are often caused by combinations of work and non-work-related factors. Many work-related complaints have multifactorial causation. Some are due to a mismatch between the worker's abilities and job demands, or person-job fit.⁷⁹

A cluster of cases in a work group suggests a greater probability of previously unidentified problems in design or management. Prevention requires the identification of associated or causative workplace and personal factors. Scientifically based recommendations concerning selection and screening of personnel, personal protection, and task or job redesign, as well as treatment and disability management, should follow. Prevention strategies may include screening and placement, engineering controls, administrative changes, personal protective equipment (PPE), education and training at all levels of the company. In addition, close attention to the psychologic needs of the employees and proper medical surveillance of the workplace should be included. There should be opportunity for contact with a health care provider if questions or complaints arise. The first avenue of investigation is to determine whether the job matches the capabilities of the individual worker.

Preventive Strategies and Tactics

Different strategies are needed to prevent first episodes of symptoms or activity limitations, to prevent recurrent episodes, to prevent or reduce lost workdays resulting from injury, to prevent chronic disability, and to reduce or prevent medical care utilization and its associated cost. Occupational health professionals should be clear about the goals of specific preventive efforts.⁷⁹

PRIMARY PREVENTION.

Primary prevention is preferable to secondary and tertiary prevention. The primary prevention of work-related disorders depends on the reduction or elimination of exposure to factors causally associated with those disorders in individuals susceptible to such stressors. In the past, emphasis has been placed on risk factors that are physical in nature, such as lighting, terminal design, and posture. However, other factors such as workers' job satisfaction and relations with supervisors have been specifically noted to have a relatively strong relationship to visual and other apparently ergonomic complaints. Primary prevention of work-related complaints may depend on reducing exposure to physical, personal, and psychosocial stressors.

SECONDARY PREVENTION.

Secondary prevention efforts are aimed at reducing disability and hastening recovery once a health concern has become apparent. This is a more targeted approach, in that it has become apparent which workers will develop complaints, illnesses, or injuries. Secondary prevention involves working in partnership with the worker. The cornerstones of this process include two-way communication, exploration of myths and misconceptions, management of expectations, bilateral or trilateral planning, and management of the episode and the situation. Modified or temporary duty is an important way to return workers to the worksite and prevents social isolation and deconditioning.

TERTIARY PREVENTION.

Tertiary prevention in the work setting involves prevention of recurrences in a patient. Initially the job tasks and person-job fit should be evaluated. Next, job or task modification or workstation changes may be necessary. Repetitions, abnormal postures (especially the type of corrective lenses in presbyopes), and other ergonomic problems should be addressed. If the individual cannot do the job as originally designed because of an impairment, reasonable accommodation should be attempted. If no accommodations are possible, job placement elsewhere or retraining may be indicated.

Beyond Prevention: Promotion

In the early 1980s there was marked intensification in preventive ophthalmology both as an academic discipline and as an institutional commitment in the United States. There has been governmental and industrial emphasis on health promotion, including on-the-job or worksite health promotion. Major industries are fostering these efforts to contain medical program costs. At the federal level, the Public Health Service of the Department of Health and Human Services has created the Office of Disease Prevention and Health Promotion to enhance morale and to improve productivity. To be successful, these programs must be voluntary and stem from a positive commitment through all levels of management, employees, and unions.^75,76

Initially, data collection is necessary to identify medical, health, and ophthalmic problems particular to a given industry or plant. This includes not only risks of specific trauma to eyes but surveys to identify the types of promotions of interest by the employees. This information may be obtained as an extension of pre-existing medical screening, injury prevention, and on-the-job initial medical care. Such an approach reinforces ongoing activities and may identify untapped resources of people, materials, and equipment within a company or plant. It can also be integrated with more traditional public health programs and prevention of ocular injury efforts such as those associated with state affiliates of the NSPB.

Such programs require a qualified and enthusiastic person who is given clear responsibility for developing promotional activities that integrate with the specific activities of the plant. Included are incentive programs such as the NSPB Wise Owl Clubs. Some clear and realistic measurable goals should be established. Programs should be given an initial trial period of at least 3 years. Ideally, all aspects of the program should be voluntary but should be supported by public relations officers and communications departments within the industry. Some aspects of the program may be offered on company time. Management should consider if programs are presented as a part of ongoing employee benefit packages or as a separate undertaking.

INITIALIZING AN EYE AND FACE SAFETY PROGRAM

Ninety-five percent of all eye injuries are preventable. Eyes, as well as other parts of the body, may be exposed to a large variety of hazards in the home, in hobbies, on the farm, and in school, as well as at the worksite.²⁷ All occupational safety programs should include protection of the eye from injury by physical, chemical, and radiologic agents. To prevent eye injuries, the correct eye protective equipment must be selected after hazards have been minimized by engineering controls.²⁷

The goal of the Occupational Safety and Health Act of 1970,⁸⁰ to ensure safe and healthy working conditions for working men and women in the nation, applies equally to other areas outside the workplace where the hazards may be exactly the same. The Occupational Safety and Health Act of 1970⁸⁰ General Duty Clause⁸⁰ requires that the “employer furnish to each of his employee's employment in the place of employment which are free from recognized hazards that are causing or are likely to cause death or serious harm to his employees.”

General Requirements on Personal Protective Equipment

OSHA 29 CFR 1910.132³⁰ has the following general requirements for PPE:

  Protective equipment, including personal protective equipment for eyes, face, head, and extremities, protective clothing, respiratory devices, and protective shields and barriers, shall be provided, used, and maintained in a sanitary and reliable condition wherever it is necessary by reason of hazards of processes or environment, chemical hazards, radiological hazards, or mechanical irritants encountered in a manner capable of causing injury or impairment in the function of any part of the body through absorption, inhalation or physical contact.
  Personal protective equipment (PPE) shall not be used as a substitute for engineering out hazards, work practice and/or administrative controls, PPE is to be used in conjunction with other controls to provide for employees' safety and health in the workplace. PPE includes all clothing and work accessories designed to create a barrier against workplace hazards.
  Static Shielding of Equipment—Barrier or deflector screens of transparent plastics can provide a clear view of a work process while protecting workers from grinding fragments, accidental sprays, or specific optical irradiations. Cutters, grinders, and fixed-location tools have long been safeguarded by properly designed static shielding. Similarly, cathode ray or television tubes have a radiation barrier glass over the surface exposed for viewing.
  Static Shielding of Personnel—Physicians are familiar with the principle of static shielding in radiology offices, in which technicians or radiologists step into separate cubicles or behind leaded glass while x-ray films are exposed. Similarly, in large molten steel pours, workers now control the operation from shielded booths that protect against heat and accidental splashes. Static shielding may be suspended from the ceiling, mounted on the floor, or constructed as a separate control area.
  Where employees provide their own PPE, the employer shall be responsible to assure its adequacy, including proper maintenance and proper sanitation. All PPE shall be of safe design and construction for the work to be performed. The employer shall assess the workplace to determine if hazards are present, or are likely to be present, which necessitate the use of PPE. Equivalent requirements are found in shipyards (29CFR 1916.152); Marine terminals (29CFR 1917.96); long shoring (29CFR 1918.108); and construction (29CFR 1926.95).

Exactly What Is PPE?

PPE includes all clothing and accessories designed to create a barrier against workplace hazards. The basic element of any PPE management program should include an in-depth evaluation of the equipment needed to protect against workplace hazards. Much of the PPE information in this chapter is framed in general terms and is intended to complement relevant regulations and manufacturers' requirements. For more specific information, refer to the OSHA standards previously cited.

Many methods of reinforcing the use of PPE have been employed. Regardless of the method, the employee should understand at the outset that his or her life may well depend on the use of PPE. PPE use should be combined with hazard awareness and training. It should be emphasized that such equipment does not eliminate a hazard. If the equipment fails, exposure will occur. Equipment must be properly fitted and maintained in a clean and serviceable condition to reduce the possibility of failure. Such PPE should be available in the event those emergency situations arise during operation.⁴¹

Steps in Developing a PPE Program

The following steps must be completed as part of and elements for developing a PPE program⁴¹:

1. Hazard assessment guidelines.
   
2. Identification of hazards.
   
3. Identifying personal eye and face protection equipment (required).
   
4. Identifying individual being exposed or potentially exposed to the identified hazards.
   
5. Assignment of PPE to individuals for protection from hazards involved in performing their essential functions of the position.
   
6. General training before initiating work.
   
7. Retraining.
   
8. Program review and evaluations.
   

Hazard Assessment Guidelines

To assess the need for eye and face protective equipment the practitioner should perform the following:

SURVEY.

Conduct a walk-through survey of the area in question.^26,41 The purpose of the survey is to identify sources of all hazards to the eyes and face of workers and coworkers. Consideration should be given to six basic hazard categories:

1. Impact.
   
2. Heat.
   
3. Chemical.
   
4. Dust.
   
5. Optical radiation.
   
6. Contusion.
   

Causes of Eye Injuries in Related Workplace Operations.⁷⁵

The following includes some of the causes of eye injuries in detail and some workplace operations where they are found:

  Dusts or powders, fumes and mists: Some sources are scaling, light grinding, spot welding, and woodworking; can also include very small flying particles.
  Flying objects or particles: Some sources include caulking, chiseling, grinding, hammering, and metalworking; these activities cause the majority of eye injuries.
  Injurious gases, vapors, and liquids: Workers handling acids or caustics, or doing welding, are subject to these hazards.
  Splashing metal: sources include babbitting, casting of hot metal, and dripping in hot metal baths.
  Thermal and radiation hazards such as heat, glare, ultraviolet and infrared rays: Sample sources are welding, metal cutting, and furnace tending.
  Lasers: Recent addition to the list of eye hazards; laser beams can present dangerous and unusual exposure, and different kinds of laser beams require different methods of eye protection.
  Electrical hazards: Sample sources are arcing and spark.

Sources of Hazards.³⁰

During the walk-through survey, one should observe

1. Sources of motion, that is, machinery or processes where any movement of tools, machine elements or particles could exist, or movement of personnel that could result in collision with stationary objects.
   
2. Sources of high temperatures that could result in facial burns, eye injury, or ignition of protective equipment, and so forth.
   
3. Types of chemical exposures.
   
4. Sources of dust.
   
5. Sources of optical radiation, that is, welding, brazing, cutting, furnaces, heat treating, high intensity lights, and so forth.
   
6. Layout of workplace and location of coworkers.
   
7. Any electrical hazards.
   
8. Ergonomic stresses both muscular and visual.
   

ORGANIZATION OF DATA.^75,76

Following the walk-through survey, data should be organized and used in the assessment of hazards. The objective is to prepare an analysis of the hazards in the environment to enable proper selection of protective equipment.

CERTIFICATION OF ASSESSMENT.⁷⁵

The employer should verify that the required workplace hazard assessment has been performed through a written certification that identifies the workplace evaluated, the person certifying that evaluation has been performed, the date of the hazard assessment, and that identifies the document as a certification of hazard assessment.

Identification of Hazards

ANALYZE DATA.

Having gathered and organized data on a workplace, one should make an estimate of the potential for eye and face injury.^14,30,75 Each of the basic hazards should be reviewed and a determination made as to the type and level of each of the hazards found in the area. The possibility of exposure to several hazards simultaneously should be considered.

DEVELOP A PPE PROGRAM.

Management dedicated to the safety and health of employees should use that evaluation to set a standard operating procedure for personnel and then train those employees to use, maintain, and clean the equipment to protect themselves against those hazards.³¹ A written PPE program should be established for the workplace. The two basic objectives of any PPE program should be to protect the wearer from safety and health hazards and to prevent injury to the wearer from incorrect use and/or malfunction of the PPE.

To accomplish these goals, a comprehensive PPE program should include

  Hazard assessment of the workplace.
  Medical monitoring.
  Environmental surveillance.
  Selection, use, maintenance, and decontamination of PPE.
  Employee training.

REASSESSMENT OF HAZARDS.

Workplace hazards should be reassessed by identifying and evaluating new equipment and processes, reviewing accident records, and reassessing the suitability of previously selected eye and face protection.³⁰ If such hazards are present or likely to be present, the employer shall

1. Select, and have each affected employee use, the types of PPE that will protect the affected employee from the new hazards identified in the hazard assessment.
   
2. Communicate selection decisions to each affected employee.
   
3. Select PPE that properly fits each affected employee.
   

Identification of Personal Eye and Face Protection Equipment

Appropriate protective equipment for the eye and face is required by OSHA (29CFR 1910.133).⁸¹ Eye and face protection is required where there is reasonable probability of preventing injury with such equipment. Other standards (ANSI Z136.1)⁸² and Z136.3⁸³ reflect on the prevention of laser burns, using similar engineering controls or personal protective goggles. All employees should acquire PPE appropriate for their activities or processes. Employees shall have types of protection suitable for the work to be performed and conveniently available. Employees should be required to use such equipment. No unprotected personnel should be subjected to hazardous environment conditions. These stipulations apply to supervisors, management personnel, and visitors while they are in hazardous areas.

A summary of a questionnaire administered to patients who presented to the Massachusetts Eye and Ear Infirmary emergency services with ocular injuries in 1985 was reported by Schein and coworkers.¹⁴ All injuries were included except those resulting from contact lens use. Only 66% of those injured at work reported that protective eyewear was provided at the job site. Of those suffering severe injury, only one third reported that protective eyewear was available. Among those injured at work, 10% stated they were wearing protective eyewear at the time of injury, and none of these injuries was severe. Ruptured globes were the most common severe injury occurring at work. In approximately one third of the cases, a history of previous eye injury was obtained. Schein illustrated the type of eyewear worn at the time of injury for the study population: 70% were wearing no glasses, 10% wore safety glasses (of which 2% had side shields), 6% wore regular glasses, and 3% wore contact lenses. One third of the subjects whose regular glasses were broken at the time of trauma suffered severe injury.

A 1980 Bureau of Labor Statistics Study⁸⁴ noted about 60 % of workers who suffered eye injuries were not wearing eye protective equipment. When asked why they were not wearing face protection at the time of the accident, workers indicated that face protection was not normally used in their type of work, or it was not required for the type of work performed at the time of the accident.

The United States Eye Injury Registry's 1996 report on 10,964 cases for the period 1988 to 2001 revealed that 62.5% of injured patients wore no protection and 2.7% wore regular streetwear spectacles, 1.5% safety eye and face protection, and 0.3% sun spectacles. The U.S. Food and Drug Administration regulation requires that all streetwear eyeglasses and sunglasses sold to the general public be shatterproof resistant.⁸⁵

TYPES OF HAZARDS VERSUS PPE.

Although PPE is part of the job in some industries such as face shields for welding it is considered a last-resort, temporary type of protection for most. The elimination of hazards in the environment, rather than PPE, is optimum.³⁰

No single combination of protective equipment and clothing is capable of protecting against all hazards. PPE should be used in conjunction with other protective methods. The use of PPE can also produce significant worker hazards, such as heat stress; physical and psychologic stress; and impairments in vision, mobility, and communication. In general, the greater the levels of PPE protection, the greater are the associated risks. Equipment and clothing should be selected that provide an adequate level of protection. Overprotection or underprotection can be hazardous and should be avoided. Using PPE improperly or in a manner unsuited to its design and purpose is worse than using no protection. Without any protection, the worker knows that he is vulnerable and will perhaps take precautions. With inadequate protection, the worker may rashly blunder into severe difficulty because of a false sense of security.

OSHA 29CFR 1910.133⁸¹ mandates the ANSI Z87.1 Eye and Face Protection⁴¹ regulations in which a table in ANSI Z87.1A correlates the basic types of eye hazards with the specific general type of spectacle and/or face shield required for the hazard. This table provides excellent guidance on the selection of types of eye/face safety equipment required. Although not mandated by OSHA, these requirements should be implemented when eye hazards exist in hobbies, at home, in school, in sports, or workplace where there is a reasonable probability of preventing injury when such equipment is used.²¹

The ANSI Z87.1⁴¹ tables on protective devices are only representative of eye and face protective devices commonly found at the time of the writing of the standard. Protective devices do not need to take the exact forms shown, but must meet the requirements of the standard. In Figures 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, the generic types from ANSI Z87.1⁴¹ are shown under the specific classes of hazards. The generic protective devices are compared with current nonprescription safety equivalent devices. Blais²⁷ submitted a new organization of existing ANSI Z87.1 tables information that enables the user to identify the specific type of lens mandated by 29CFR 1910.133.⁸¹

SPECIAL PURPOSES LENSES.

Requirements regarding special purpose lens are outlined in ANSI Z87.1(a)-1991.⁴¹ Such lenses should meet all requirements of the standard except for the transmittance requirements of OSHA 29CFR 1910.133, table on “Filter Lenses for Protection Against Radiant Energy.”⁸¹ They may be used at the discretion of the individual responsible for the eye safety program.

General.

Special purpose lenses provide eye protection while performing visual tasks that require unusual filtering of light. Examples include, but are not limited to: didymium-containing, cobalt-containing, uniformly tinted and photochromic lenses, and lenses prescribed by an eye specialist for particular vision problems. However, many such lenses offer inadequate ultraviolet and/or infrared protection. Caution should be exercised in their use. For each application,^41,76 the responsible individual should ensure that the proper ultraviolet, infrared, and visible protection is provided. Spectral transmittance data shall be available to buyers on request. Both viewing areas of a protector must meet the transmittance matching requirements of the standard on spectacles⁸¹ (Section 8), face shields (Section 9), goggles (Section 10), welding helmets, and hand shields (Section 11).

Photochromic lenses are used throughout the world and more than 500 million lenses have been sold.^27,42 The photochromic lens is a common type of special purpose lens, which darkens when exposed to sunlight and fades when removed from the sunlight. This lens is frequently used to provide comfortable vision for a wide range of ambient illumination. In daylight, outdoors, when the photochromic lenses darken to function as sunglasses, they protect the eye dark-adaptation process. It is well known that those who wear sunglasses in sunlight adapt to dark environments up to twice as fast as those who do not. In transient conditions, that is, coming in from lighter outdoor conditions to a darker indoor condition, wearing photochromic lenses can actually provide better, more stable, and more comfortable vision under a broad variety of work conditions. Vision function in the transition to and from brighter light is superior when photochromic rather than clear lenses are used. Because the fading process is not instantaneous, photochromic lenses should be used with care in operations requiring critical acuity, or fast reaction to visual stimuli, particularly in operations in which the wearer passes from outdoors to indoors in the course of the job; for example, a forklift operator passing from outdoors to indoors. Corning, the manufacturer of glass items, has hundreds of millions of man-years of experience with the use of photochromic eyeglasses without any reported safety problems. Transitions Optical, Inc. has a polycarbonate lens. Transitions with Advanced Quantum Technologies is appropriate for persons who need a versatile technologically advanced lens that quickly adjusts to changing light conditions, moving from virtually clear indoors to a dark tint outdoors. They are scratch resistant, compatible with antireflective coatings, can be designed as single, multifocal (including progressive addition) lenses, and occupational lenses (special lenses for specific tasks—double segs). Although photochromic lenses absorb ultraviolet light, they should not be used as a substitute for the proper protector in hazardous optical radiation environments.

The company's safety professional is in the best position to determine when tinted or variable tint lenses should or should not be used based on the awareness of the workplace conditions. The use of photochromic lenses in industry situations is dependent on the visual demands of the tasks and the visual needs of the wearer. The decision on the need for photochromic lenses can be made by evaluation of the workplace requirements by the employer in consultation with the employee's eye doctor.

LIMITATIONS.^27,29,71

In general, lenses having low luminous transmittance should not be worn indoors, except when needed for protection from optical radiation, because indoor light levels tend to be only adequate. Care should be exercised in conjunction with wearing such lenses for driving vehicles with tinted windshields or for night driving.

LEGAL RESPONSIBILITY DISPENSOR OF EYE SAFETY EQUIPMENT^86,87

Tort Law

Probably the most important standard of care as far as the medical professional is concerned is the tort law. Tort law is that branch of law that resolves disputes. It says what a reasonable practitioner in the same community would do under the same circumstances and determines the expert witnesses.

Malpractice

To have malpractice, you have to have a duty. One has to establish the relationship with the patient and have an obligation to provide care; only in these circumstances can one commit negligence. Negligence is established by the expert testimony at the time of trial, and it had to result in damage.

Negligence in this setting is very, very important because it comes in two big areas (1) product liability and (2) failure to warn, and that is when the prescribers and dispensors are at high risk. Negligence occurs if the dispensors either knew or should have known that the product was defective or inadequate and failed to inform the user, such as open eye guards as racquetball goggles. If the product is defective, it may result in eye injury.

1. Be fully informed regarding patient activities whether during hobbies, duties at home, in sports or at work.
   
2. Provide the individual with the maximum visual efficiency possible to fulfill the visual requirements of ANSI Z87.1 and 29CFR 1910.133, ANSI Z136.1 (laser) ANSI Z136.3 medical laser.
   
3. In those cases in which the individual cannot fulfill the visual requirements for the specific function, a request for accommodation is required as long as the lack of visual function does not cause a substantial threat to the individual or a substantial threat to others (ADA).
   
4. Provide a description of each worker's essential functions including the industrial environment. Hobby and sport interest also may be recorded.
   
5. When presbyopic lenses are advised, provide for the lack of accommodation to perform the visual task efficiently and effectively in accordance with the essential functions of the position with an adequate physiologic amplitude of accommodation. Progressive add lenses have been shown to be very efficient in fulfilling these requirements.
   
6. Prescribe lenses to allow the performance of essential visual tasks comfortably with good visual ergonomics and good body ergonomics.
   
7. If the practitioner is responsible for safety equipment, the practitioner must ensure that there has been no negligence, that is, product liability or failure to warn.
   

The Occupational health and eye practitioner teams must provide the following to the individual³¹

1. Guidance regarding what essential tasks he or she may perform safely with instructions regarding the PPE required to do so.
   
2. Advice regarding those tasks that represent a substantial threat to himself or herself and to others, and, therefore, those tasks should not be performed.
   

OSHA mandates in the code of Federal Regulation 29CFR 1910.133⁸¹ and 1910.132^30,75,76 that eye and face PPE is required where there is reasonable probability of preventing injury when such equipment is used. Although not mandated by OSHA, these requirements should apply to those cases in which similar hazards exists in hobbies, at home, in school, and in sports, where there is a reasonable probability of preventing injury when such equipment is used. The ANSI Z87.1-1989A, 1991⁸¹ on Eye and Face Protective Devices and ANSI Z136.1⁸² and Z136.3⁸³ on Lasers sets forth the requirements on the design, construction, testing, and use of the PPE devices.

The occupational health team must (1) provide guidance to the practitioner regarding what essential tasks the worker must perform safely, with instructions regarding the PPE required to do so and (2) provide guidance to the individual regarding those tasks for which he or she is a substantial threat to himself or herself and to others and, therefore, should not perform those tasks.

To fulfill the requirements of OSHA, appropriate eye and face PPE shall be prescribed by the ophthalmologist so that the individual employer might purchase, in accordance with the previous regulations and the employer's rules of operation, the eye and face PPE to prevent injury from the potential eye hazards.

It is the dispensing practitioner's responsibility to see that there has been no negligence through product liability and especially failure to warn the individual about the purpose for and the shortfalls of the items prescribed or dispensed.

It was not until 1940 that industry and ophthalmology combined forces in an attempt to establish standards of visual efficiency that would permit the selection of suitable candidates for prospective jobs. Much of the work that was performed at the Occupational Research Center at Purdue University under the direction of Tiffin and his coworkers apparently was lost in a fire. There has been no structured research since that time to update the published work of Kuhn and coworkers. Tiffin, Kuhn, and Novak did not consider what medical (visual) surveillance should be performed and applied to particular hazards. Research of this information is required and should be compiled so that eye and occupational practitioners may reference it. The last textbook on industrial and occupational ophthalmology was in 1973.⁸⁸

Eye hazards are the most serious of all nonfatal industrial accident hazards. They rank a high second only to death in seriousness. It is true that much has been accomplished toward the alleviation of these conditions by the development of safety equipment during the last decade, particularly through the work of such organizations as the National Safety Council; the Safety Institute of America; the NSPB; the American Society of Safety Engineers; and the various state industrial commissions, trade associations, and technical societies that have interested themselves in accident prevention and, in general, in improvement of work conditions.

All that has been accomplished thus far is only the beginning because much work remains to be completed to generate the visual standards required to perform all the eye and vision essential functions of the multiple positions and occupations in the country. No texts providing a composite of this information have been written since the 1950s.⁸⁹ Much research must be developed and financial support obtained to update the visual requirements for specific tasks so that this information might be applied to allow the individuals to perform the task safely, efficiently, and without problems resulting from muscular or visual ergonomic abnormalities.

There continues to be a significant shortfall in the training of employees, employers, first responders, and professionals in the prevention and diagnosis of eye injuries and especially in the treatment of chemical injuries of the eyes. As Kuhn,²³ Fox,⁸⁸ and Resnick⁴ have stated, many accomplishments have been completed and are working well but much is left to be completed.

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