If you are talking about an infant or a very small child, being left in total darkness will impair the development of vision, leaving the baby "unable to see". They would have to have their vision totally impaired up past the critical age of about 8 years old. But even a baby left in darkness for 1 week would still develop vision when they were brought into the light, as they still had plenty of plasticity in the system and time to develop vision.

So yeah, that is probably where he got confused. It's easier for a kitten, because they mature at a more rapid rate, and the critical period is much smaller for them.