How can I tell if my cat is blind or has impaired vision? I think that this is quite a good question because although often it may be obvious, on other occasions it might not. Cats are very good at compensating and the structure of the eye may look normal but the retina not working properly. In fact, most cases of blindness are not evident on general observation of the eye itself according to the veterinarians who wrote the excellent book Cat Owner’s Home Veterinary Handbook upon which I rely a lot. An ophthalmologist will have to confirm partial or full blindness but I briefly discuss some tests that you might find useful.
RELATED: Feline Hypertension – there are more articles on blind cats below.
I’m told that shining a bright light into a cat’s eyes to test whether the iris constricts the pupil is not a guaranteed test because this may be a reflex action. And it won’t tell you if the cat’s brain has the ability to create an image from the signal received from the eye.
There are some indications that you might rely on. Normal activities that a domestic cat is involved with and which require eye and body coordination such as playing with on a ball or other toy, or jumping from a sofa might look clumsier. And if a cat has poor vision and the room is badly lit, they may bump into furniture or they may hold their nose close to the ground and feel their way forward with their whiskers which are pointed forward.
The veterinarians say that “the eyesight of older cats begins to fail shortly after the onset of deafness”. Therefore, they have to rely on memory to find their way around. Although, as you probably know, blind cats do manage extraordinarily well provided they are within familiar surroundings, which means the owner should not rearrange the furniture as blind cats rely on a mental map of where it is.
Clearly, cats with impaired vision or blind cats should be full-time indoor cats or if allowed to go outside it should only be under supervision or on a lead.
In elderly cats, hypertension i.e. high blood pressure, is a common cause of blindness (see link above).
RELATED: My Cat has Dilated Pupils (always)
Below are some more articles on blindness.