Residual vision in humans who have been monocularly deprived of pattern stimulation in early life

Spatio-temporal sensitivity at and above threshold was investigated in a group of patients who exhibited visual loss secondary to uniocular congenital cataract which was present within the first year of life and later removed. The results fall into two general categories depending upon the severity of the visual loss and in particular upon the nature of the temporal loss. In the group exhibiting less severe amblyopia, contrast sensitivity for high and medium spatial frequencies was attenuated to a similar extent for all temporal frequencies. In the group exhibiting more severe amblyopia no form vision a was present; only temporal perception remained. In these cases a greater loss of flicker threshold sensitivity occurred at higher temporal frequencies. Supra-threshold tests revealed that movement perception was effectively normal in both of these groups. These results demonstrate that stimulus deprivation amblyopia, while different in some respects from anisometropic amblyopia is more similar to that condition than to strabismic amblyopia Previous animal results derived from monocular lid suture in cat and monkey are compared with these findings.