Why do you think the cats have to cross their eyes to correct this problem?

Cats may appear to cross their eyes when they are focusing on objects close to them, as this helps them judge distance and depth more accurately. This behavior can also be a result of their natural hunting instincts, allowing them to better track movement. Additionally, some cats may have a slight strabismus, which can cause their eyes to appear crossed even when they are not actively focusing. Overall, this eye adjustment is a normal part of their visual processing.