Constriction of the Visual Field of Children After Early Visual Deprivation
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PURPOSE: We measured the extent of the monocular visual fields of children deprived of normal visual experience and examined the influence of the timing and duration of deprivation, of whether deprivation was monocular or binocular, of having patched the fellow eye, and of optical factors. METHODS: The Goldmann perimeter and a 6.4' stimulus of either 31.8 cd/m2 (target 12e) or of 318 cd/m2 (target 14e) were used to test 44 children treated for a dense and central cataract in one (n = 25) or both (n = 31) eyes that developed before 6 years of age. Then, the influence of optical factors was assessed in two adults treated for a late-onset, unilateral cataract and in two children treated for unilateral congenital cataract. RESULTS: Compared with age norms or the normal fellow eye, all children treated for cataract showed a restricted field, especially temporally, even when deprivation began as late as 6 years of age and lasted less than 6 months. The restrictions were larger than those shown by the adults who developed cataracts. The restrictions were larger after longer deprivation and monocular deprivation than after binocular deprivation. However, children who regularly patched the fellow nondeprived eye and, therefore, experienced less interocular competition, exhibited smaller restrictions temporally. Neither visual acuity nor optical factors could account for all of the restrictions in the deprived children. CONCLUSIONS: The development of the visual field is vulnerable to the effects of deprivation, especially to unilateral deprivation and to long deprivation. The losses likely reflect alterations in the visual pathways subserving peripheral vision.
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