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Cat glaucoma
The eye constantly produces a clear liquid which must evacuate at the same rate. When this drainage is blocked, the pressure inside the eye rises: this is glaucoma. This pressure crushes the optic nerve and the retina. Destroyed cells do no...
What is it?
The eye constantly produces a clear liquid which must evacuate at the same rate. When this drainage is blocked, the pressure inside the eye rises: this is glaucoma.
This pressure crushes the optic nerve and the retina. Destroyed cells do not regenerate, which explains why lost vision does not return.
In cats, glaucoma is almost always the consequence of another eye disease, most often uveitis. The progression can be slow and discreet, or sudden, with loss of vision within a few hours.
Key point
Absolute ophthalmological emergency: high pressure can destroy the optic nerve and cause loss of vision within a few hours. A red, painful or cloudy eye appears the same day.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Red, painful, watery eye.
Dilated pupil which no longer narrows in the light.
Surface of the eye cloudy, as if veiled with blue.
Eye that appears larger than the other, in installed forms.
Loss of vision on this side: the cat bumps into things, hesitates on the stairs, refuses to jump.
Pain often expressed discreetly: cat that hides, eats less, remains prostrate, refuses caresses on the head.
In brutal forms, the eye changes appearance in a few hours.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Secondary glaucoma predominates in cats: the outflow of fluid is blocked by the consequences of another disease.
Chronic uveitis is the most common cause, with inflammatory cells blocking the outflow tract.
A tumor developed in the eye, especially from the iris or lymphoma, can interfere with the flow.
A shift in the lens, bleeding in the eye or trauma are other possible causes.
Primary glaucoma, linked to an abnormality of the evacuation angle without other disease, exists but remains rare in cats.
History of uveitis or chronic ocular inflammation.
Older cats, in whom tumor causes are more common.
Infection with feline leukosis, feline immunodeficiency or toxoplasmosis, which cause uveitis.
Old eye trauma.
Lens disease.
Glaucoma already occurred in the other eye.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The measurement of intraocular pressure, carried out with a device placed delicately on the cornea, is the central examination: it confirms the diagnosis in a few seconds and without pain.
Both eyes are systematically measured and compared.
A complete eye exam looks for the cause: signs of uveitis, mass, position of the lens, condition of the retina and optic nerve.
A general assessment, with blood work and viral tests, is often necessary, as feline glaucoma is rarely isolated.
Repeated pressure checks punctuate the treatment, because the balance can break quickly.
Treatment
The immediate goal is to reduce the pressure to save what vision can be saved, then treat the cause.
Eye drops that reduce fluid production or facilitate its evacuation are prescribed; some are contraindicated depending on the cause, which prohibits any self-medication.
Anti-inflammatory treatment is associated when glaucoma follows uveitis.
The pain is treated generally: an eye under pressure causes constant pain.
When the eye is permanently blind and remains painful despite treatment, surgical intervention is suggested. Removing the eye may seem impressive, but it removes chronic pain and cats adapt remarkably well to it.
The other eye is closely monitored throughout the cat's life.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Treat any uveitis or eye inflammation quickly and completely: this is the main lever for prevention in cats.
Have eye pressure measured when monitoring an eye disease, even if the eye appears calm.
Detect and prevent feline infections through vaccination, testing and limiting fighting.
Include an eye exam in the older cat's annual checkup.
Never use non-prescribed eye drops: certain products increase the pressure.
Possible complications
Permanent blindness of the affected eye, sometimes within a few hours in brutal forms.
Progressive increase in eye volume, with exposure and ulceration of the cornea.
Chronic pain, often underestimated because the cat rarely expresses it.
Second eye damage when the underlying cause is not controlled.
When to see a veterinarian
Your cat's eye is red, cloudy or appears larger than the other: seek emergency medical attention.
The pupil remains dilated and no longer reacts to light.
Your cat bumps into things, no longer jumps, looks for its bearings.
He hides, refuses to be touched on the head or stops eating.
The appearance of the eye changes in a few hours: every hour counts for vision.
Your cat is being monitored for uveitis and its eye condition is changing.
Prognosis
The vision already lost does not return: the whole challenge is to preserve the one that remains, hence the urgent nature of the treatment.
Glaucoma taken in the very first hours can have its pressure controlled and part of the vision preserved.
In secondary forms, the prognosis largely depends on the causative disease; the comfort of the cat can almost always be ensured, including through surgery.
Frequently asked questions
Can my cat live normally with only one eye?
Yes. Cats compensate very well, relying on smell, hearing and vibrissae. A painful blind eye removed is often an immediate relief.
How to recognize glaucoma pain in a cat?
It rarely manifests itself through complaints. Instead, we observe a cat that hides, sleeps more, eats less and no longer accepts petting on the head.
Can lost vision return with treatment?
No, destroyed optic nerve cells do not regenerate. Treatment aims to save remaining vision and remove pain.
Will the second eye be affected?
It's possible, especially if the underlying cause persists. It is monitored at each check and treated preventively in certain situations.
References
AAFP — American Association of Feline Practitioners
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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