Fig. 10. Pupil perimetry response in the normal visual field compared with visual light sense perimetry in the same eye. The contraction amplitude (in millimeters excision) of the pupil is plotted as a function of perimetric location to a 1.7-degree 1000 apostilb intensity light in the pupil field. Note that the pupil contracts the most near the center of the visual field, and the response drops off in the periphery. In the visual field the threshold for light detection is given in decibels. A more sensitive area has a higher decibel threshold level.