Fig. 10. Visual acuity (resolution) as a function of age according to three techniques: optokinetic nystagmus (OKN), preferential looking (PL), and visually evoked cortical potential (VECP). (Used with permission from: Fulton AB, Hansen RM, Manning KA: Measuring visual acuity in infants. Surv Ophthalmol 25:325, 1981.)