Cloudy eyes in cats can result from several different conditions, ranging from harmless age-related changes to serious infections or diseases that need prompt treatment. The appearance of the cloudiness, your cat’s age, and whether one or both eyes are affected all help narrow down the cause. Here’s what might be going on and what to watch for.
Age-Related Lens Changes
The most common and least concerning cause of cloudy eyes in older cats is a condition called nuclear sclerosis. It typically appears after 8 to 10 years of age. Throughout your cat’s life, the lens continuously produces new fiber cells. Over time, the center of the lens gets compressed and denser, creating a faint bluish-gray haze. This looks alarming, but it does not cause significant vision loss. Your cat can still see through the lens, and the condition doesn’t require treatment.
Nuclear sclerosis is often confused with cataracts, but the two are quite different. Cataracts are actual opacities in the lens that block light. A small, early-stage cataract might affect only 10 to 15 percent of the lens and cause no noticeable vision problems. A mature cataract, however, covers the entire lens and significantly impairs vision. Cataracts can also trigger inflammation inside the eye, which may lead to glaucoma, a painful condition involving elevated eye pressure. A veterinarian can distinguish between the two by dilating your cat’s pupils with medicated eye drops and examining the lens directly.
Corneal Ulcers
The cornea is the clear outer surface of the eye, and when it’s damaged, it can turn cloudy or develop a bluish haze. Corneal ulcers happen when cells in the outermost layer of the cornea are lost faster than new ones can replace them. Common causes include scratches from other animals, foreign objects, and infections. Signs include squinting, discharge from the eye, sensitivity to bright light, and rubbing at the face. In severe cases, an ulcer can perforate the cornea entirely.
Vets diagnose corneal ulcers using a simple dye test. A few drops of a water-soluble fluorescent dye are placed on the eye. Healthy corneal surface repels the dye, but any area where the protective outer layer has been lost absorbs it, leaving a bright green stain that’s easy to see. If the deepest part of the ulcer doesn’t absorb the dye at all, the damage has reached the innermost membrane of the cornea, which is a more urgent situation. If dye-stained fluid is seen leaking from the surface, the cornea has actually been punctured.
Feline Herpesvirus and Corneal Scarring
Feline herpesvirus (FHV-1) is one of the most common infectious causes of corneal cloudiness in cats. The virus can directly damage the surface cells of the cornea, producing distinctive branching ulcers. These small, tree-like patterns on the cornea are considered almost uniquely characteristic of herpesvirus. When multiple ulcers merge together, they create larger, map-shaped lesions.
The bigger concern with herpesvirus is long-term damage. The virus can lie dormant and reactivate repeatedly over a cat’s lifetime. Each flare-up damages the deeper structural layers of the cornea, and over time this leads to permanent scarring and clouding. Chronic cases may also involve swelling and new blood vessel growth across the cornea. If your cat has a history of upper respiratory infections (sneezing, nasal discharge, watery eyes as a kitten), herpesvirus is a likely suspect behind recurring eye cloudiness.
Uveitis: Inflammation Inside the Eye
Uveitis is inflammation of the inner structures of the eye, and it’s one of the more serious causes of cloudiness in cats. The eye may look hazy because inflammatory cells, proteins, or even blood leak into the fluid-filled front chamber. Unlike corneal problems that affect the surface, uveitis involves deeper structures and often signals a systemic disease elsewhere in the body.
Several major feline infections are known to cause uveitis. Feline infectious peritonitis (FIP) commonly produces inflammation in both eyes, with white blood cells, red blood cells, and clotting proteins flooding the front chamber. Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) can also trigger chronic eye inflammation. Toxoplasmosis, a parasitic infection, frequently affects the back of the eye but can involve the front as well. Fungal infections like blastomycosis cause a particularly aggressive form of inflammation. Because uveitis often points to something happening beyond the eye itself, a vet will typically recommend blood work and infectious disease testing.
Glaucoma
Glaucoma occurs when fluid pressure inside the eye rises too high, damaging internal structures and sometimes causing the cornea to swell and look cloudy. Normal eye pressure in cats averages around 12 mmHg. Pressure readings of 25 mmHg or higher, or a difference of 12 mmHg or more between the two eyes, are red flags.
What makes feline glaucoma tricky is that cats rarely show obvious pain even when pressure is dangerously high. Unlike dogs, who typically develop a dramatically swollen, red, painful eye, cats with glaucoma often maintain a normal appetite and activity level. The corneal swelling that’s a hallmark of canine glaucoma is less pronounced in cats at similar pressure levels. In young cats, the eye may visibly enlarge over time. Because cats hide their discomfort so well, glaucoma is often caught late, making regular eye exams especially important for older cats.
High Blood Pressure
Cats with systolic blood pressure at or above 160 mmHg are at risk for damage to the blood vessels inside the eye. This is most common in older cats with kidney disease or an overactive thyroid. High blood pressure can cause bleeding inside the eye, retinal detachment, and a cloudy or reddened appearance. Sudden blindness, where a cat starts bumping into furniture or seems disoriented in familiar rooms, can be the first noticeable sign that blood pressure has been dangerously elevated.
How to Spot Eye Pain in Cats
Cats are experts at hiding discomfort, but there are reliable physical clues. Squinting or holding the eyelids partially closed is one of the most consistent signs of eye pain. You may also notice the third eyelid, the pinkish membrane at the inner corner of the eye, creeping up to partially cover the eye. This happens passively when a painful eye retracts slightly into the socket. Other signs include redness, excessive tearing from one eye, and rubbing or pawing at the face. Some cats become withdrawn or start hiding more than usual.
When Cloudy Eyes Need Urgent Care
Some eye changes can wait for a regular vet appointment, but others can’t. A cloudy or bluish haze that appears suddenly (rather than gradually over months) warrants same-day attention. The same is true for unequal pupil sizes, visible blood inside the eye, thick or colored discharge, a bulging or sunken appearance to the eye, and any signs of sudden vision loss like bumping into furniture, hesitating in familiar spaces, or fixed, widely dilated pupils that don’t respond to light.
If the cloudiness developed slowly and your cat is older than eight or nine with no signs of pain or vision trouble, nuclear sclerosis is the most likely explanation. But because cataracts, glaucoma, and uveitis can all look similar to the untrained eye, a proper exam is the only way to know for sure.
Treatment Options
Treatment depends entirely on the cause. Nuclear sclerosis needs no intervention. Corneal ulcers are typically managed with medicated eye drops to prevent infection and promote healing, and most resolve within one to two weeks if caught early. Herpesvirus-related eye disease may require antiviral medication and often needs long-term management since the virus can reactivate. Uveitis treatment focuses on controlling inflammation in the eye while addressing whatever underlying infection or disease is driving it. Glaucoma requires pressure-lowering medications and sometimes surgery if the pressure can’t be controlled.
For cataracts that significantly impair vision, surgical removal is an option. The procedure uses ultrasound to break up and remove the clouded lens. The Royal Veterinary College reports a success rate of approximately 90 percent, with nine out of ten eyes achieving a favorable outcome. It’s a specialized procedure performed by veterinary ophthalmologists, and costs vary widely by location and whether one or both eyes are treated.