Rapid improvement in the acuity of infants after visual input

Visual acuity was assessed in 28 human infants who had been deprived of all patterned visual input by cataracts in one or both eyes until they were tr eated at 1 week to 9 months of age. Immediately after treatment, acuity was no better than that of normal newborns. Acuity improved significantly over the next month, with some improvement apparent after as little as 1 hour o f visual input. Unlike findings at older ages, the pattern of results was t he same for eyes treated for monocular and for binocular deprivation. The r esults indicate that patterned visual input is necessary for the postnatal improvement of human visual acuity and that the onset of such input initiat es rapid functional development.