A 10 day period of total darkness has been shown to either block or erase the severe effects on vision of a prior short period of monocular deprivation (MD) in kittens depending on whether darkness is contiguous or is delayed with respect to the period of MD. We have extended these earlier findings from kittens for which the period of MD began at one month and lasted for a week to more clinically relevant situations where MD began near birth and lasted for 6 weeks or more. Despite the far longer MD and the absence of prior binocular vision, all animals recovered normal visual acuity in the previously deprived eye. As before, when the period of darkness followed immediately after MD the vision of both eyes was initially very poor but thereafter the acuity of each eye increased gradually and equally to attain normal levels in about 7 weeks. By contrast, when darkness was introduced 8 weeks after MD, the visual acuity of the deprived eye recovered quickly to normal levels in just a week without any change in the vision of the fellow (non‐deprived) eye. Short (15 or 30 min) periods of illumination each day during an otherwise 10 day period of darkness obliterated all the benefits for vision, and a 5 day period of darkness was also completely ineffective. Measurements of depth perception indicated that despite possessing normal visual acuity in both eyes, only about a quarter showed evidence of having attained normal stereoscopic vision. This article is protected by copyright. All rights reserved