Cataracts in cats appear as a white, bluish-white, or milky cloudiness inside the eye, located behind the pupil rather than on the surface. In early stages, you might see only a small foggy spot or a few tiny opaque flecks deep within the eye. As a cataract progresses, the cloudiness spreads until the entire pupil looks like frosted glass, completely blocking the normal dark or reflective appearance you’d expect to see.
What Each Stage Looks Like
Veterinary ophthalmologists classify cataracts into four stages, and each one looks noticeably different when you shine a light toward your cat’s eye.
Incipient cataracts are the earliest stage. You may see small, focal white or crystalline spots within the lens, but the eye still reflects light normally. If you shine a flashlight at your cat’s eye in a dim room, you’ll still see the characteristic green or yellow glow (called a tapetal reflex) bouncing back at you. Most owners don’t catch cataracts at this stage because the spots are small and easy to miss.
Immature cataracts cover more of the lens. The cloudiness is more obvious, appearing as a hazy, whitish film behind the pupil, but the lens surface still looks smooth and you can still get that reflective glow when light hits the eye. Your cat can still see at this point, though their vision is partially obscured.
Mature cataracts are what most people picture when they think of cataracts. The entire lens is opaque, giving the pupil a solid white or bluish-white appearance. The eye no longer reflects light back at you, so instead of that normal glow, you just see a dense, milky disc. At this stage, the cat is essentially blind in the affected eye.
Hypermature cataracts have been present long enough that the lens starts to shrink and wrinkle. The surface of the lens, which looked smooth in earlier stages, becomes visibly creased or puckered. Some hypermature cataracts partially reabsorb, which can let a little light through again, making the reflective glow inconsistent or patchy.
Cataracts vs. Normal Aging Changes
Not every cloudy-looking eye is a cataract. Older cats commonly develop a condition called nuclear sclerosis, which also makes the eyes look hazy. The difference matters because nuclear sclerosis is harmless and rarely affects vision, while cataracts can lead to blindness and complications.
Nuclear sclerosis happens when the center of the lens gets compressed over time, making it denser and slightly cloudy. It gives the eye a faint bluish-gray haze, but the cloudiness is more translucent than opaque. If you look closely, you can usually still see through to the back of the eye. A cataract, by contrast, creates a distinctly white opacity that blocks your view into the eye. A veterinarian can tell the difference quickly using a specialized light instrument, so if you’re unsure what you’re seeing, an exam will give you a clear answer.
What Causes Cataracts in Cats
Cataracts in cats are less common than in dogs, and in many cases, the cause is never identified. When a cause is found, it’s often one of these:
- Inflammation inside the eye (uveitis): This is the most frequent known trigger in cats. Chronic inflammation damages the lens over time.
- Aging: Older cats develop cataracts as a natural consequence of lens deterioration.
- Trauma: A puncture wound or blunt injury to the eye can rupture the lens capsule and trigger rapid cataract formation.
- Metabolic problems: Diabetes and difficulty metabolizing certain proteins can cause lens changes, though diabetes-related cataracts are rare in cats compared to dogs.
- Genetics: Certain breeds carry a higher risk, including Persians, Himalayans, Russian Blues, British Shorthairs, Birmans, and Bengals. Bengal cats in particular have shown a high prevalence of cataracts in young animals, suggesting a hereditary basis.
Cataracts can also form after exposure to toxic substances, radiation, or electric shock, though these are uncommon scenarios.
Behavioral Signs of Vision Loss
Cats are remarkably good at compensating for gradual vision loss, which means a cataract can progress significantly before you notice behavioral changes. When vision does deteriorate enough to affect daily life, the signs tend to be subtle at first. Your cat may hesitate before jumping onto furniture, misjudge distances, or bump into objects that have been moved from their usual spots.
More advanced vision loss produces more obvious behavior. Cats that lose vision quickly over days or weeks often appear confused, fearful, and withdrawn. They may freeze in place when startled rather than running away. You might notice them struggling to find their food bowl, avoiding stairs, or staying close to walls as they navigate. A cat that suddenly seems intimidated by its own home is showing a classic sign of recent blindness.
What Happens if Cataracts Go Untreated
Cataracts aren’t just a cosmetic issue. As a cataract matures, proteins leak from the deteriorating lens and trigger inflammation inside the eye. This chronic, low-grade inflammation can be painful and, left unchecked, can lead to secondary problems like glaucoma (dangerous pressure buildup inside the eye). A hypermature cataract with a wrinkled, shrunken lens is particularly prone to causing these complications.
Even if your cat seems to be coping well with reduced vision, the inflammatory cascade happening inside the eye can cause damage that makes future treatment more difficult or less successful.
How Cataracts Are Diagnosed
A veterinarian can spot a cataract during a standard eye exam, but fully evaluating it requires specialized tools. A slit lamp, which projects a thin beam of light into the eye, lets the vet pinpoint exactly where the opacity is within the lens and determine its stage. This instrument can detect early crystallization and tiny fluid pockets in the lens long before they’re visible to the naked eye.
If the cataract is dense enough to block the view of the back of the eye, an ultrasound may be used to check the retina. This is important because there’s no point in removing a cataract if the retina behind it isn’t healthy enough to restore vision. Pressure inside the eye is also measured to rule out glaucoma.
Surgical Treatment and Recovery
The only way to remove a cataract is surgery. The procedure, called phacoemulsification, uses ultrasonic vibrations to break up the cloudy lens, which is then suctioned out. According to the Royal Veterinary College, approximately 90% of eyes that undergo this surgery have a favorable outcome.
Vision recovery varies. Some cats can see immediately after the procedure, while most experience a gradual improvement over the first several days. The recovery period involves eye drops to manage inflammation and prevent infection, along with an e-collar to keep your cat from rubbing the eye. Not every cataract requires surgery. If the cataract is small, not progressing, and not causing inflammation, monitoring may be the better approach. The decision depends on the stage, your cat’s overall eye health, and whether the cataract is actively affecting quality of life.