Feline Ophthalmology Series

July 9, 2026

Part Three: Feline Blindness

Susan Cook Henry

Blindness in cats can result from of a wide range of causes, such as trauma, physical challenges, hereditary traits, and illness, to name a few. If you have noticed your cat seeming to forget where it is, exhibit a halting gait, navigate stairs poorly, sit and meow for no apparent reason, or hug the walls of the rooms in your home when finding its way … you may have reason to believe your cat is having trouble getting its bearings, or more precisely – seeing its location.

Regular veterinary care is very important in keeping your cat’s health at its best, and a check of its eyes should be part of any general exam. For the most part, feline eyes function the same way ours do and have the same components:¹

• Cornea, the transparent outer covering of the eyeball;
• Pupil, the black “hole” in the center of the eye that permits the entry of light from the environment;
• Iris, the round, pigmented membrane that surrounds the pupil and contracts or expands to regulate the amount of incoming light;
• Lens, a transparent structure that adjusts its shape as needed to focus the light rays;
• Retina, a sensitive membrane that lines the interior surface of the eyeball, receives the focused light impulses that have entered through the lens, and sends them along to the brain as visual information;
• Optic nerve, the conduit leading from the retina to the brain.

Being familiar with the visible structures of your cat’s eye is a good thing. While the retina and optic nerve are only seen with proper ocular instruments, your visual observations at home will be key if you have noticed any unusual behavior, and looked at the eyes to see if anything appears abnormal. Is there excessive discharge in the corners of the eyes? Are the eyelids or tissues inside red and swollen? Is your cat squinting when the eyes should normally be wide open? Do you see any cloudiness behind the corneal surface or the pupil? These are symptoms that might require a closer look by a veterinarian.

Leading Causes of Feline Blindness

“The interior of the eye is divided into three chambers or compartments referred to as the anterior (front) chamber, posterior (back) chamber and vitreous chamber. The anterior chamber is located between the cornea and the iris, and contains aqueous humor (a clear fluid produced by the ciliary body). The posterior chamber is located between the iris and lens and also contains aqueous humor. The vitreous chamber is behind the lens and in front of the retina. It is occupied by vitreous, a gel-like substance that helps to maintain the round shape of the eye.”²

Glaucoma and cataracts are the leading anterior causes of blindness in cats,³ meaning problems can start in the forward (anterior, posterior) parts of the eye – behind the cornea, from in front the iris to the back of the lens. Glaucoma (a condition marked by excessive fluid pressure within the eyeball that can cause it to harden¹) is diagnosed by checking the pressure of the aqueous humor of the eye with a tonometer, a special instrument which shoots a puff of air against the front of the eyeball. Although glaucoma is not common in cats in general, it can appear as primary glaucoma (a hereditary trait that will generally occur in both eyes), while secondary glaucoma is much more random. The latter can occur in just one eye, often as a result of uveitis – a condition causing gradual cloudiness and buildup of pressure within the eye. This can happen over months or longer, often causing an eye to look larger and/or appear to bulge. Uveitis is usually associated with feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), feline infectious peritonitis (FIP), and toxoplasmosis.⁴ Vision loss will progress over time; although glaucoma is incurable, topical medications can help alleviate the pressure and relieve the associated pain.

A cataract is a film which causes gradual clouding of vision. Cataracts form inside the lens (which sits forward of the vitreous chamber) and are often visible through a dilated pupil. Some cataracts “develop as the result of an animal’s inability to metabolize proteins and other body chemicals, or they may in rare cases be a byproduct of such conditions as diabetes or hypertension. Other potential causes include traumatic injury that results in a perforated lens, and exposure to certain drugs or toxic substances, radiation, or electric shock.”⁵

In some cases with kittens and mature cats that have qualified as good candidates, cataracts can be successfully removed and a new lens implanted, a procedure which takes about an hour.

The next most common cause of feline blindness is retinal detachment, “a condition in which the retina becomes separated from its underlying tissue, typically resulting from a leakage or oversupply of fluid between the two layers.”¹ This condition is usually a result of high blood pressure, an overactive thyroid gland, or kidney disease. If caught early, repair may be possible; however, in most cases, it will result in permanent blindness.

Traumatic injuries are also common. Corneal lacerations are of concern, so in a multi-cat household, keeping claws trimmed is very important to help avoid such injuries resulting from intense play or fighting. Corneal ulcers and associated sequestration (which were discussed in the first part of this series) – if left untreated – can result in permanent, vision-blocking scars. Regular monitoring of your cat’s eyes is important in discovering potential issues early so treatment can be most effective.

Resources

1. Feline Vision Problems: A Host of Possible Causes; Cornell Feline Health Center, n.d. Accessed April 24, 2026. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-vision-problems-host-possible-causes
2. Structure and Function of the Eyes in Cats; Dr. Bari Spielman, August 3, 2015; Accessed April 24, 2026. https://www.petplace.com/article/cats/pet-health/structure-and-function-of-the-eyes-in-cats
3. Daniel Biros, DVM, DACVO; Approaches to Diagnosing Blindness in Cats, March 2022; Accessed April 24, 2026. https://www.mspca.org/angell_services/approaches-to-diagnosing-blindness-in-cats/
4. Feline Glaucoma; Cornell Feline Health Center, n.d. Accessed April 24, 2026. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-glaucoma
5. Feline Cataracts; Cornell Feline Health Center, n.d. Accessed April 24, 2026. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-cataracts