Burmese Cat

　　If a cat suddenly loses its sight, before it learns to adapt, it may show some abnormal behaviors: it might be unwilling to leave its sleeping spot, avoid using the litter box because it can't find it. It may become withdrawn and call endlessly when confused and needing comfort.

　　You can test the cat’s vision like this: cover one of the cat’s eyes and see if the other eye follows your moving finger, and check if there is a response to fingers moving toward the uncovered eye.

　　You can also use a flashlight directed at the uncovered eye, turning it on and off, to see if there is any reaction. However, this method is not 100% accurate because blindness does not necessarily occur at the eyeball; sometimes the pupil may react to light, but normal visual signals are not properly processed by the brain.

　　If the cat is blind in only one eye, it may attack or defend against sudden movements on the blind side. If the cat’s vision differs between both eyes, it may frequently turn its head to look to compensate for the lost field of view, and may have problems with depth perception because it has lost stereoscopic vision. (Source：PetsZone)