When to see a vet urgently
Contact a vet the same day if your cat's eye looks painful or suddenly changes appearance:
- Your cat keeps it closed, constantly squints or rubs it.
- The eye is red and cloudy or contains visible blood.
- The pupils suddenly differ in size or one looks misshapen.
- Your cat bumps into things, cannot find objects or seems to have lost vision.
You can find a vet near you.
Overview
Inflammation of the iris and ciliary body disrupts fluid circulation within the eye, alters pupil responses and causes severe pain. Prolonged disease can produce adhesions called synechiae, raised intraocular pressure and even glaucoma. Iridocyclitis can affect one or both eyes and often signals systemic disease.
The ciliary body produces aqueous humour, which nourishes internal eye structures. Inflammation allows more protein and inflammatory cells into this fluid. This can cause cloudiness even without pus on the surface. Anterior uveitis means inflammation at the front of the eye; inflammation elsewhere in the uveal tract may also involve the back. Your vet therefore examines more than visible redness.
Synechiae are adhesions in which the inflamed iris sticks to the lens, for example. They can alter pupil shape and obstruct fluid flow. However, pressure does not rise in every uveitis case: acute inflammation often lowers it below normal.
Causes
The main causes of iridocyclitis in cats include:
- Viral infections, including feline infectious peritonitis, FeLV, FIV and herpesvirus.
- Parasitic disease, including toxoplasmosis.
- Bacterial infections, including Lyme disease and mycoplasmosis.
- Fungal infections, including histoplasmosis and cryptococcosis.
- Eye injuries from bites, scratches or foreign objects.
- Eye tumours or metastases.
- Immune and autoimmune processes.
The list does not mean every infection is equally common or equally firmly established as a feline anterior uveitis cause. Pathogens are assessed according to symptoms, exposure and findings. Observations of tick-borne disease in dogs, for example, cannot be applied directly to cats. A positive infection test alone does not establish the eye inflammation's cause.
If no clear cause is found, inflammation may be considered idiopathic, or of unknown cause. Immune-mediated inflammation is considered after other causes are excluded; no single specific blood test establishes it. Disease within the eye, such as lens damage or displacement, can also trigger inflammation without systemic infection.
Risk factors
Iridocyclitis is more common in cats that:
- Have chronic viral infections.
- Live in crowded conditions, such as shelters or groups of kittens.
- Are older.
- Have had eye injuries.
- Have cancer or immune system disorders.
Risks depend on the underlying disease. Uveitis also occurs in young cats, so old age is not required. Dense cat populations can affect transmission of certain infections but do not identify the cause alone. Information on universally applicable age and housing risk factors is limited.
Symptoms
Typical signs of anterior uveitis include:
- Eye redness and swelling.
- A constricted pupil (miosis) responding poorly to light.
- Cloudiness of the cornea or anterior chamber.
- Light sensitivity and tearing.
- Tiredness and appetite loss with systemic infections.
- Severe pain, with pawing at the eye or squinting.
- Reduced or lost vision with complications.
You may notice withdrawal from a bright room or avoidance of touch around the head. Your cat may not scratch even a painful eye. Iris colour changes or an irregular pupil can also relate to inflammation. Symptom severity alone does not establish the amount of internal damage.
Corneal ulcers, conjunctivitis and glaucoma cause similar symptoms. A photograph alone cannot distinguish them. A normal-looking opposite eye also does not rule out systemic disease.
Complications and consequences
Untreated iridocyclitis can lead to:
- Posterior synechiae, or adhesions between iris and lens.
- Glaucoma, with raised intraocular pressure.
- Cataracts.
- Chronic inflammation and shrinkage of the eye.
- Complete blindness.
Not every cat develops complications. However, inflammatory debris and scarring can block aqueous humour drainage, causing secondary glaucoma. Raised pressure can permanently damage vision. Pressure problems may persist after the original inflammation settles if drainage routes have been damaged.
Diagnosis at the vet
Diagnosis is based on:
- Ophthalmoscopy and biomicroscopy.
- Intraocular pressure measurement to rule out glaucoma.
- Eye ultrasound to assess cloudy internal fluid.
- A complete blood count and biochemistry.
- FeLV, FIV and toxoplasmosis tests; FIP is assessed from the whole picture, including blood and aqueous humour testing, rather than coronavirus antibodies alone.
- Examination of eye discharge where needed.
Biomicroscopy examines the front of the eye using magnification and light. Fluorescein staining looks for a corneal ulcer. Pressure in both eyes and, where possible, the fundi are examined. Normal pressure alone does not exclude uveitis, and a high reading may indicate inflammation-related drainage failure.
Ultrasound helps examine internal structures, such as a suspected tumour or retinal detachment. It is particularly useful when cloudiness obscures the view. General examination looks for fever, weight loss and other organ changes. Alongside blood and urine tests where needed, imaging is selected according to findings; not every cat needs the same investigation package.
Toxoplasma IgG antibodies may be present in a healthy cat previously infected. Results are interpreted alongside other tests. Coronavirus antibodies similarly show exposure, rather than FIP alone. Nor does improvement during antiviral treatment confirm FIP. Eye and systemic signs can resemble one another across different diseases, so fundus examination is also part of assessment.
Treatment
A vet experienced in ophthalmology prescribes treatment after examining the cornea:
- Anti-inflammatory eye drops, with corticosteroid drops used only if there is no corneal ulcer.
- Pupil-dilating drops that relieve spasm, reducing pain and adhesion risk.
- Treatment of the underlying infection, injury or tumour.
- Pressure monitoring throughout inflammation.
A systemic cause is often sought, so drops alone are usually insufficient.
Topical treatment may sometimes control eye inflammation, but a confirmed systemic disease needs its own care. Oral medicines are considered according to extent, severity and cause. Antibiotics do not automatically suit every uveitis. Possible raised pressure also affects eye medicine selection.
Corticosteroid drops can delay corneal ulcer healing and cause serious complications. Do not start drops left over from previous treatment yourself. Even anaesthetic drops used during examination are unsuitable as repeated home pain relief: they can damage the cornea. Medicine selection requires knowing which eye structure is affected.
Home care and monitoring
Give only medicines prescribed for this cat, following instructions. Ask for a demonstration if giving drops is difficult. Report unsuccessful administration or resistance because of pain. A vet-recommended protective collar may prevent rubbing. Do not press the eye or force the lids open to look inside.
Monitor squinting, tearing, redness, cloudiness and movement in familiar surroundings. Also record appetite, general health and medicines used. New or increasing pain, sudden vision loss or deterioration needs contact before the planned follow-up. Eye appearance does not reliably indicate pressure.
Prognosis
Prognosis depends on the cause, severity and established damage. Repeat examinations check treatment effectiveness even if your cat opens the eye normally. Recurrent inflammation may need long-term medicines and monitoring for adverse effects. Preserved vision and pain control are assessed separately: reduced redness alone does not establish complete recovery.
Prevention
Iridocyclitis cannot be completely prevented, but risk may be reduced through:
- Regular vaccination.
- Monitoring and treatment of chronic infections.
- Preventing eye injuries, particularly in outdoor cats.
- Regular veterinary examinations, especially with systemic disease.
Vaccines are planned according to living conditions and infection risk. They do not protect against every listed infection or every uveitis cause. Avoiding raw meat and hunting can reduce toxoplasmosis risk. These measures cannot prevent tumours or every immune-mediated inflammation.
What it means for owners
Iridocyclitis in cats is more than an eye disease: it often signals systemic viral or parasitic illness. Remember that redness, cloudiness and eye pain are reasons to seek immediate care from a veterinary ophthalmologist. Earlier treatment improves the chance of preserving vision.
Do not delay initial examination of a painful eye while waiting for a specialist appointment. A general vet or emergency service can assess urgency, examine the eye and arrange further care.
This material provides general information and does not replace veterinary advice. Contact a vet immediately if symptoms develop.
Frequently asked questions
Can anterior uveitis in cats get better?
Inflammation can be controlled in many cases, but prognosis depends on cause and complications. Some cats need long-term treatment. Established glaucomatous vision damage may not recover when inflammation settles.
Is anterior uveitis contagious?
Eye inflammation itself does not establish transmission risk. Infection, injury, a tumour or immune-mediated disease may be responsible. Testing other cats and infection prevention are planned according to the confirmed or suspected cause.
Can eye pressure be normal with uveitis?
Yes. Pressure is often low in acute inflammation but can be normal or raised. Measurement is considered with other findings and repeated during treatment.
Can I use my cat's old eye drops?
Do not start previous drops without veterinary instructions. A new symptom may have a different cause, and corticosteroid drops, for example, can worsen a corneal ulcer-related problem.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Anterior Uveitis in Small Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Uveitis in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Uveitis in Dogs and Cats, American College of Veterinary Ophthalmologists, accessed 2026-11-03.
- Guideline for Feline Infectious Peritonitis, ABCD, accessed 2026-11-03.
- Toxoplasmosis in Cats, Cornell Feline Health Centre, accessed 2026-11-03.
- Clinical and clinicopathologic features of an undifferentiated resolving uveitis in kittens similar to that seen with feline infectious peritonitis, Journal of the American Veterinary Medical Association, accessed 2026-11-03.
- Glaucoma in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Corneal Ulcers in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- 2024 guidelines for the vaccination of dogs and cats, World Small Animal Veterinary Association, accessed 2026-11-03.