Part of the show Science of Sight, Eye Diseases and Animal Vision
My husband has recently developed a squint overnight. Why is that?
It's probably because one of the muscles is not working properly. There are six muscles and it's probably because one or maybe two of them are not working very well. So it could be a nerve being pinched somewhere, but as it happened overnight, it's more likely that a blood vessel blocked. So the supply to the nerve is damaged and the nerve doesn't work very well. Usually it will tend to recover in a few weeks.