Glaucoma in cats is rising eye pressure that damages the retina and optic nerve — painful, often subtle, and a true emergency for vision. Look for cloudy or bluish color to the cornea, an enlarged eye, squinting, hiding, or going off food. Pressure must be measured with a tonometer; without treatment within 24 to 48 hours, permanent blindness in the affected eye is likely.
Last reviewed: May 2026
What Glaucoma Actually Is
Glaucoma is sustained elevation of intraocular pressure (IOP) above the normal feline range of about 15 to 25 mm Hg. High pressure compresses the retinal blood supply and damages the optic nerve; vision can be permanently lost within hours to days of severe pressure rise. Unlike dogs, cats almost always develop secondary glaucoma — caused by another eye disease such as uveitis, lens luxation, FeLV/FIV-related inflammation, or intraocular tumor.
Subtle Signs Owners Miss
Cats hide eye pain extremely well. Early signs are often nothing more than squinting, slight tearing, hiding, reduced appetite, or sleeping more. By the time the eye looks visibly cloudy or enlarged (buphthalmos), pressure has often been high for days. About 70 percent of cats with newly diagnosed glaucoma have already lost some vision in the affected eye at presentation.
The Eye Itself Changes
Cloudy or bluish corneal haze, a dilated pupil that doesn't constrict to light, redness of the conjunctiva, and visible enlargement of the globe over weeks are the classic eye findings. A cat with red, hazy eyes and small pupil change in only one eye should be assumed to have glaucoma or uveitis until proven otherwise.
Why Underlying Causes Matter
Because feline glaucoma is almost always secondary, the workup includes searching for the trigger: FeLV/FIV testing, blood pressure check, complete blood work, and often ocular ultrasound. As described in the AAFP Feline Retrovirus Guidelines, 2020, chronic FeLV- or FIV-associated uveitis is one of the more common drivers in cats over 8 years old.
Treatment and Prognosis
Emergency pressure-lowering drops (dorzolamide, timolol) plus oral pain medication start in the exam room. Long-term treatment combines topical medications with addressing the underlying disease (steroid drops for uveitis, surgery for lens luxation, etc.). Eyes that are blind and painful are sometimes removed (enucleation) for comfort. Many cats with glaucoma in one eye eventually develop it in the other, so the unaffected eye is monitored closely.
Cost of Diagnosis and Treatment
An emergency eye exam with tonometry runs $100 to $300, basic bloodwork and FeLV/FIV testing add $150 to $300, and ocular ultrasound is $200 to $500. Topical glaucoma drops cost $40 to $100 a month for long-term management. Enucleation surgery for a blind painful eye is typically $1,200 to $2,500 and is curative for pain in that eye. Catching glaucoma in the first 24 to 48 hours dramatically improves vision-saving odds and avoids more expensive late-stage surgery.
When to See a Vet
Call your vet today if:
- Squinting, cloudy, or red eye lasting more than a few hours
- Pupil in one eye is bigger than the other and doesn't change with light
- Tearing or rubbing the face along surfaces
- Hiding, reduced appetite, or new lethargy in a cat with any eye change
- Visible enlargement of one eye compared with the other
Go to the ER immediately if:
- Sudden, severely cloudy or bluish eye
- Eye visibly enlarging over hours
- Pawing at the eye, vocalizing, or rubbing it raw
- Loss of vision (cat walking into things, missing furniture jumps)
- Eye proptosis (the globe pushed forward beyond the lids — true emergency)
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Frequently Asked Questions
Can a cat live a normal life if blind in one eye from glaucoma?
Yes. Cats adapt very well to vision loss in one eye and continue normal activity — jumping, hunting, navigating — within a few weeks. The priority is making sure the eye is not painful; an enucleated eye is more comfortable than a chronically pressurized one. Many indoor cats with one good eye live full lifespans.
How much does treating glaucoma in a cat cost?
Emergency eye exam with tonometry runs $100 to $300. Topical pressure-lowering drops are $40 to $100 a month long-term. Bloodwork plus FeLV/FIV testing adds $150 to $300. Ocular ultrasound is $200 to $500. Enucleation surgery for a chronically painful blind eye is $1,200 to $2,500. Referral to a veterinary ophthalmologist runs $200 to $400 for the initial consult plus diagnostics.
Is glaucoma painful for cats?
Yes, even though they don't show it the way humans do. High eye pressure causes deep, headache-like pain. The behavioral signs are subtle — hiding, hunched posture, reduced appetite, reluctance to be touched on the head — but pressures over about 30 mm Hg are clearly painful. This is why same-day treatment matters.
Can glaucoma be cured with drops alone?
Drops can control pressure for months to years in some cats, but glaucoma is usually a chronic condition rather than something cured. The drops control pressure and slow progression; the underlying cause (uveitis, tumor, lens luxation) usually needs separate treatment. Cats can switch between several drops over the course of their disease.
Will my cat go blind in the other eye too?
About 50 percent of cats with glaucoma in one eye eventually develop it in the other within 1 to 2 years, especially if the underlying cause (chronic uveitis from FeLV/FIV or autoimmune disease) affects both. The unaffected eye is monitored every 1 to 3 months with pressure checks, and prophylactic drops are sometimes started.
Still Not Sure if Your Cat Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of the affected eye in good light — both head-on and from the side so we can see if it's enlarged, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.