Our feline family members are susceptible to many of the conditions that can affect humans' vision as well as others that are unique to cats. Fortunately, many eye diseases in cats can be caught early and treated, and some can be reversed. Even if your cat does lose its vision, chances are it can continue to live a full and happy life.
As in humans, blindness in cats can be caused by a variety of problems. If you notice symptoms that indicate an eye problem, have your cat examined by a veterinarian. Treat any eye injury as an emergency situation, and seek medical attention immediately.
Cataracts
Cataracts, or opacity of the lenses, is rarer in cats than in dogs or people. A cataract can develop due to the presence of another condition, like infection, or all on its own. Cataracts can also lead to other problems, including glaucoma. It is important to have your cat evaluated if you notice cataract formation. Surgery to remove the affected lens is possible in some cats, and lens implants are sometimes used to approximate normal vision.
Glaucoma
Glaucoma is indicated by increased pressure within the eye and can lead to blindness in cats. Glaucoma is also extremely painful but can be treated with medications to help reduce the intraocular pressure and prevent damage to the retina and optic nerve. In severe cases, treatment may require hospitalization or possibly surgery to remove the affected eye(s). Glaucoma can be a primary disease or develop as a result of other eye problems.
Eye Tumors
Cats can develop different types of tumors within or on the surface of the eye. Removal of the eye is often necessary, but a prosthesis may be inserted to retain a more normal appearance. Secondary glaucoma may be caused by a tumor.
Progressive Retinal Atrophy
Progressive retinal atrophy, or PRA, is an untreatable condition that is most likely inherited. It progresses slowly but eventually results in total blindness. The condition is not painful, and because of its gradual nature, cats usually learn to cope quite well with their decreasing ability to see.
Conjunctivitis
Conjunctivitis is inflammation of the pink membranes that line the eyelids, often causing reddening, swelling, drainage, and squinting eyes. Feline herpesvirus, calicivirus, and chlamydiosis are common causes of conjunctivitis in cats. Cold-like symptoms may be seen as well. Treatment is generally supportive in nature. In some cases, symptoms may recur over the lifetime of the cat. Stress is a key factor in repeated instances of feline herpesvirus.
Attendant corneal involvement can compromise vision, so it is important that a cat with conjunctivitis be seen by a veterinarian or, if necessary, by a veterinary ophthalmologist.
Feline Hypertension
Untreated feline hypertension is a relatively common cause of sudden blindness. Hypertension often accompanies heart disease, diabetes, hyperthyroidism, and kidney disease. Cats with any of those conditions should be monitored closely by a veterinarian for evidence of hypertension. Hypertension can also develop with no identifiable underlying cause, although this does not occur as frequently in cats as it does in people.
There are few early symptoms to watch for at home, but two possible signs are dilated pupils that do not respond normally to light and the appearance of blood in the eye chamber. Sudden blindness is always considered a medical emergency, and the cat should be seen by a veterinarian without delay.
Feline hypertension is handled by treating any underlying conditions and with medications that reduce the cat's blood pressure.
How to Help Your Blind Cat
Seeing a treasured cat go blind, either gradually or suddenly, can be a devastating experience because we tend to equate vision loss in cats with human blindness. We need to remember, though, that cats are terrifically resilient. Cats don't need a cane to find their way around, nor do they need to learn braille or hire a driver (they have you!). They will use their senses of smell, hearing, and touch (such as with whiskers on their legs and face) to compensate for their vision loss. Cats can adapt so well that casual visitors may not even be aware that a cat is blind.
If your cat is blind, you can help a great deal by keeping their normal routine and environment as unchanged as possible. Its food dish, bed, litter box, and other accoutrements should be kept in their normal places. Try to avoid moving furniture, and keep other potential stumbling blocks out of its way. You can warn your cat of your approach by speaking to it or clapping your hands. (Your cat will also feel the vibrations of your footsteps on most floors.) Of course, any unsupervised access to the outdoors should be eliminated for safety reasons.
Most importantly, relax and enjoy your cat. Whether blind or seeing, its feelings for you haven't changed.