Glaucoma in Cats: Increased Eye Pressure Diagnosis and Treatment

Last updated: May 16, 2026

What Glaucoma in Cats Actually Is

Glaucoma in cats is a painful, vision-threatening condition in which fluid pressure inside the eye climbs above what the optic nerve and retina can tolerate. The eye constantly produces a clear fluid called aqueous humor, which normally drains out through a tiny mesh near the iris. When that drainage falters, the pressure rises, and the delicate retinal cells and optic nerve fibers begin to die.

The feline form of this disease behaves quite differently from the canine version. In dogs, glaucoma is most often a primary, breed-linked drainage defect that strikes one eye first and then threatens the other. In cats, glaucoma is overwhelmingly secondary, meaning another eye problem, almost always chronic uveitis, has clogged or scarred the drainage angle and pushed pressure up over weeks to months.

Because feline glaucoma rides on the back of inflammation, the warning signs can be subtle and easily mistaken for a simple “cloudy eye” or aging change. Cats are also famously stoic about ocular pain. By the time most owners notice, the affected eye is already losing vision, which is why a fast workup with an ophthalmology-aware veterinarian matters so much.

Why Cats Develop Glaucoma Differently Than Dogs

The vast majority of feline glaucoma cases are classified as secondary glaucoma. The most common upstream cause is chronic anterior uveitis, an inflammatory state of the front of the eye, which can be triggered by feline infectious peritonitis, feline leukemia virus, feline immunodeficiency virus, toxoplasmosis, herpesvirus, and immune-mediated disease. Inflammatory cells, fibrin, and adhesions called synechiae block the drainage angle.

Other secondary causes include intraocular tumors, especially diffuse iris melanoma and lymphoma, lens luxation, mature cataracts that leak protein, and prior ocular trauma that scars the angle. Primary glaucoma, where the angle is malformed without any other disease, does occur in cats but is genuinely rare and most often reported in Burmese, Siamese, and Persian cats.

This “secondary by default” pattern is why your veterinary team will not stop at confirming high pressure. They will work backward to figure out what is driving the inflammation, because controlling pressure without addressing the underlying disease almost always fails.

Warning Signs You Should Never Ignore

Early feline glaucoma is sneaky. The first changes are often a mildly cloudy or hazy cornea, a subtly enlarged pupil that does not constrict normally in light, slight redness of the white of the eye, and tearing. Owners frequently chalk these up to allergies or aging.

As pressure climbs, more obvious signs appear. The eye may look noticeably bigger than its partner, a phenomenon called buphthalmos. The pupil may stay dilated even in bright light. You may see squinting, light sensitivity, withdrawal from petting around the head, decreased appetite, and hiding. Some cats bump into furniture, miss familiar jumps, or seem startled when approached from the affected side.

If you ever see a clearly enlarged eye, sudden cloudiness with a fixed dilated pupil, or any combination of squinting plus a dull-looking eye, treat it as urgent and get to a veterinarian the same day. Glaucoma damage is measured in hours, not days.

How Veterinarians Diagnose Feline Glaucoma

Your primary veterinarian will start with a thorough history and a hands-on eye exam. They will look at how the eyes track, examine the cornea and iris with magnification, check pupil responses, and measure intraocular pressure with a tonometer. Normal feline pressure usually sits in the high teens to low twenties; consistently elevated pressures over the upper limit, especially with clinical signs, point to glaucoma.

Because feline glaucoma is almost always secondary, expect the workup to widen. Bloodwork, FeLV/FIV testing, toxoplasmosis titers, and sometimes feline coronavirus testing or chest radiographs are common. Ocular ultrasound looks for hidden masses or lens problems behind a cloudy cornea. Fundic exam, when possible, evaluates the optic nerve and retina.

For complex or vision-salvageable cases, your vet will likely recommend a referral to a board-certified veterinary ophthalmologist through the American College of Veterinary Ophthalmologists. An ACVO ophthalmologist has tools like gonioscopy and electroretinography that map the drainage angle and measure retinal function in ways general practice cannot match.

Medical Treatment Options

Treatment goals are pain control, pressure reduction, and protection of any remaining vision. Topical medications are the cornerstone. Carbonic anhydrase inhibitor drops slow fluid production. Beta-blocker drops add another layer of pressure control. Prostaglandin analogs, which are first-line in dogs, are usually less effective in cats and used selectively. Combination drops can simplify dosing.

Because uveitis is so often the engine, anti-inflammatory therapy is just as important as pressure-lowering drops. Topical steroids or NSAIDs and, in some cases, systemic anti-inflammatories control the underlying inflammation. If an infectious cause is identified, the targeted antiviral, antibiotic, or anti-protozoal therapy is layered in.

Pain management deserves real attention. Glaucomatous eyes hurt. Your vet may prescribe oral pain control during flares. Owners often underestimate how much better their cat acts once pressure is controlled and pain is treated.

Surgical and Salvage Procedures

When medical therapy fails or vision is already lost, surgical options exist. In eyes that still have functional vision, ophthalmologists may perform laser cyclophotocoagulation to reduce fluid production or place a drainage shunt to bypass the blocked angle. These procedures preserve vision in some cats but rarely cure the disease and often require continued drops.

For permanently blind, painful eyes, the most humane and reliable solution is enucleation, surgical removal of the eye, or evisceration with placement of an intraocular prosthesis. Owners often dread enucleation, but cats adapt remarkably well and almost always feel better the same week. A blind, painful eye is a daily source of suffering; removing it ends the pain.

If a tumor is the underlying cause, removing the eye also lets the pathologist examine it and tell you whether further staging or treatment is needed. Diffuse iris melanoma in particular benefits from earlier rather than later enucleation.

Prognosis and Long-Term Vision Outlook

Honest prognosis matters here. By the time feline glaucoma is diagnosed, the affected eye has often already lost most of its useful vision, especially if pressure has been elevated for weeks. Saving vision in an already-affected eye is the harder fight; protecting the second eye and keeping the cat comfortable is the realistic goal.

Cats with well-controlled underlying uveitis and committed daily eye-drop owners can do very well for years, including cats who lose one eye and live happily with the other. Cats with aggressive intraocular tumors carry a more guarded prognosis, depending on tumor type and metastatic behavior.

Quality of life, not eye numbers, should drive decisions. A blind cat who eats, plays, snuggles, and navigates the home is a happy cat. Vision is wonderful when we can save it, and absolutely worth chasing, but it is not a prerequisite for a great feline life.

Living With and Adopting a Cat With Glaucoma

If your cat is partially or fully blind from glaucoma, small environmental tweaks make an enormous difference. Keep furniture, food bowls, and litter boxes in the same spots. Avoid leaving sharp-edged obstacles in walking paths. Use scent and texture cues, like a soft mat at the food station or a particular rug at the litter area. Talk before you touch so you do not startle.

Glaucoma cats are absolutely adoptable, and rescues regularly place them with loving families. If you are considering bringing one home, our adopting a blind cat guide walks through the realistic day-one expectations, and our blind cat home setup guide covers the practical environmental adjustments. For cats who have lost a single eye, the one-eyed cat adoption guide is a great place to start.

Many of these cats arrive at shelters precisely because their previous owners felt overwhelmed by the diagnosis. The truth on the ground is that with reasonable medical follow-up and a stable home, these cats often outlive their conditions and become some of the most affectionate companions in the rescue.

Cost, Insurance, and Planning Ahead

Feline glaucoma can be a long, prescription-driven condition. Daily eye drops, recheck pressure measurements, and ongoing treatment of any underlying inflammatory or infectious disease all add up. Specialty ophthalmology visits, advanced imaging, and surgical procedures are meaningfully more expensive than general practice.

Pet insurance enrolled before symptoms appear can offset a real share of costs; most policies will not cover what they consider pre-existing eye disease, so timing matters. Ask your veterinary team about regional cost ranges, payment plans, CareCredit, or hospital scratch funds. Many ophthalmology practices will work with you on a treatment plan that is medically reasonable and financially sustainable.

Plan, too, for the moment when an affected eye stops responding to drops and surgical removal becomes the kindest path. Setting that expectation early lets you make the decision from a place of comfort, not crisis.

Related Reading and Companion Conditions

Glaucoma in cats almost never travels alone. Understanding the conditions that can drive it makes you a better advocate at every vet visit. Our guide to uveitis in cats covers the most common upstream cause in detail. Feline cataracts can both cause and complicate glaucoma. Cats with chronic eye irritation may also struggle with conjunctivitis or recurrent eye infections.

If your cat has had a corneal complication, the corneal ulcer guide and the eye discharge causes overview may help you sort out which symptom belongs with which problem. Owners noticing a haze or color change in the iris should also read about feline iris melanoma.

Whenever you see a new eye sign, get it checked promptly. The eye is small, and its problems compound fast.

Frequently Asked Questions

Can glaucoma in cats be cured?

Glaucoma is managed, not cured. Medical and surgical therapies can control pressure and pain for years, but the underlying drainage problem persists. Treating the underlying uveitis or tumor gives the best long-term outlook.

Is glaucoma painful for my cat?

Yes. Elevated pressure is genuinely painful, even though cats hide it well. Many owners only realize how much pain their cat was in once treatment or enucleation relieves it and the cat becomes more affectionate, hungry, and active.

Will my cat go blind?

Vision in the affected eye is often already compromised by diagnosis. With prompt treatment and aggressive management of underlying disease, the second eye can frequently be protected. Even fully blind cats live very full lives indoors.

Should I see a veterinary ophthalmologist?

If your primary vet diagnoses glaucoma, an ACVO board-certified ophthalmologist offers diagnostic tools and surgical options general practice cannot. Even one consultation can clarify the best long-term plan.

How can I make the home easier for a cat with vision loss?

Keep furniture and resources in fixed locations, avoid clutter on walking paths, use textured mats as landmarks, and talk before you touch. Most cats with vision loss adapt within a few weeks if their environment stays consistent.