Visual acuity and behavior of monocularly deprived monkeys after retinal lesions

One eyelid of each of three Macaca nemestrina monkeys was sutured shut at 3 weeks of age. One animal had the central 10 degrees of the open eye retina lesioned at 3 weeks of age (EL1), a second at 9 months of age (LL1), and the third had no lesion (MD1). After a reverse suture at 9 months of age, the deprived eye was tested for grating acuity, visual behavior, and visual field. EL1 tested positively on all behavioral tasks by 1 month and showed good visual ability to negotiate a playroom but never performed better than 20/1,250 on grating acuity. MD1 showed little visual behavior in the playroom but tested at 20/400 acuity. LL1 rapidly recovered all aspects of visual behavior and tested at 20/80 visual acuity. Perimetry shows that LL1 and EL1 respond mainly in the central portion of the deprived eye visual field but not to the periphery or the monocular segment. We conclude that removal of the open eye retina after the critical period allows much visual recovery by the deprived eye but that removal of the open eye retina within the critical period does not prevent many of the effects of monocular deprivation.