When to see a vet urgently
Contact a vet promptly if you notice any of the following:
- Your cat keeps an eye closed or constantly squints and rubs it.
- The eye becomes cloudy, bluish or markedly red.
- The pupils differ in size or your cat seems to see less well than before.
- The eye problem began after an injury or chemical splash.
Do not monitor a painful eye at home for several days hoping it will improve. You can find a vet near you.
Overview
Eyelid movements are normally controlled by nerve impulses that produce blinking and protect the eye. In blepharospasm, this function is disrupted: the eyelids contract too frequently and forcefully. In cats, this appears as squinting, eye closure and increased blinking. The sign may be temporary or chronic depending on its underlying cause.
Squinting is often a practical sign of eye pain even when you cannot see a wound. A superficial corneal injury, for example, may be almost invisible to the naked eye yet very painful. A cat may protect the eye by holding its lids tightly closed or rubbing its head against a surface. Rubbing can then cause further damage to the eye's surface.
Assessment of eyelid movement also considers whether the lids close normally and whether hairs touch the eye. Forceful contraction from blepharospasm can turn the eyelid edge inwards. This is called spastic entropion. Hairs then rub against the cornea and increase pain, sustaining the eyelid contraction. However, not every inward-turning eyelid results from spasm.
Causes
The most common causes of blepharospasm in cats include:
- corneal damage, including scratches, ulcers and erosions,
- allergic, bacterial or viral conjunctivitis,
- uveitis, inflammation of the eye's uveal tissues,
- glaucoma, with raised pressure inside the eye,
- foreign bodies, including sand, dust or hair,
- dry eye from insufficient tears,
- eyelid or eye injuries,
- bright light or chemical irritants.
Uveitis means inflammation of one or more parts of the uveal tract: the iris, ciliary body and choroid may be involved. With inflammation at the front of the eye, redness and a smaller pupil may occur. In glaucoma, pressure within the eye is too high. Both can cause squinting and cannot reliably be distinguished by appearance alone.
Conjunctivitis in cats often involves infectious factors, particularly herpesvirus. Eye symptoms from an environmental allergen are one possibility, but allergy should not be assumed to cause painful squinting without examination. An eye that appears to have another problem may also have concurrent corneal damage.
Risk factors
- cats with chronic eye diseases,
- cats with outdoor access, because of injury and foreign body risk,
- older cats with age-related eye diseases,
- breeds prone to eye disease, such as Persians and Exotic Shorthairs.
Research on individual risk factors for blepharospasm in cats is limited, so the list does not identify the cause. However, in flat-faced cats such as Persians, eye anatomy can predispose to surface damage: the eye protrudes, eyelids may not close fully and hairs can rub the cornea. Some of these animals have reduced corneal sensation and blinking, so even serious damage may produce less apparent pain than expected.
Symptoms
Blepharospasm is easy to recognise from the following signs:
- frequent blinking or squinting,
- difficulty opening the eye,
- increased tear production,
- light sensitivity, with avoidance of bright light,
- restlessness and rubbing the eyes with a paw,
- red, swollen eyelids.
One or both eyes may be affected. Clear tears alone do not show a problem is mild, as internal eye inflammation and corneal ulcers can also cause watering. With glaucoma, the eye may look cloudy and the pupil may dilate. Eye pain may also make a cat hide or become less active than usual.
Tell the vet whether symptoms began suddenly, whether an eye injury is possible and whether nasal discharge, sneezing or other illness signs are present. Mention previous eye medicines, including leftover drops. A description or photograph can help if symptoms fluctuate, but does not replace examination.
Possible complications
Without treatment, blepharospasm can cause:
- corneal ulcers and scarring,
- chronic inflammation,
- loss of sight,
- spread of infection to other eye structures.
Consequences usually arise primarily from the disease causing the squinting. A corneal ulcer, for example, is often the cause of blepharospasm rather than simply a later consequence. However, rubbing and eyelid malposition can worsen surface damage. Glaucoma or severe uveitis can harm vision without a large visible wound on the eye's surface. Not every squinting case progresses to blindness, but the cause needs timely investigation.
Diagnosis at the vet
The vet investigates the cause using:
- an eye examination,
- fluorescein staining of the cornea to detect damage,
- eye pressure measurement,
- laboratory tests if infection is suspected,
- ophthalmoscopy or eye ultrasound when needed.
The eye surface, eyelids and tears
Fluorescein staining applies dye to the eye's surface, where it adheres to damaged cornea. This reveals small lesions that are otherwise difficult to see. If an ulcer is deep, longstanding or suspected to be infected, samples for cytology or culture may be taken. The order of sampling and staining is planned according to the investigation.
Eyelid position and blinking are assessed separately. Pain can alter eyelid position, so the vet determines whether inward turning is structural or pain-related. Tear production and the eye surface can be assessed if dryness or incomplete closure is suspected.
Eye pressure and internal structures
Eye pressure is measured with a tonometer. Pressure is often lower than normal in uveitis and raised in glaucoma, but the overall picture and possible complications determine interpretation. Measurement helps distinguish situations requiring very different treatments.
Ophthalmoscopy examines the eye's internal structures. Ultrasound may be needed if cloudiness prevents a view inside or another internal change is suspected. Investigation of uveitis also assesses general health, as a systemic disease may underlie it. Further tests, such as blood or urine analysis, depend on findings.
Herpesvirus test results are interpreted alongside symptoms. The virus can remain dormant and shedding can vary. A single sample therefore does not always establish the cause of current eye pain on its own. Local eye examination is needed even in a cat previously diagnosed with herpesvirus.
Treatment and follow-up
Treatment targets the cause of pain
Treatment differs for corneal damage, glaucoma, uveitis and eyelid abnormalities. In glaucoma, pressure must be lowered rapidly to protect vision and eye structures. Uveitis treatment addresses inflammation and pain and any systemic disease. A deep or poorly healing corneal ulcer may need surgery. A severe case requires assessment by a vet with expertise in eye disease.
Spastic entropion may improve when the painful eye disease is treated. Eyelid position can be corrected temporarily when needed. The need for permanent surgery is assessed separately; a pain-triggered change does not automatically require the same solution as a structural defect.
Do not start old eye drops on your own. A steroid-containing product can delay corneal ulcer healing or make it worse. The vet checks the cornea before selecting such medication. Local anaesthetic eye drops used during examination are also unsuitable for repeated home treatment because they can damage the cornea.
Home care and follow-up checks
Prevent rubbing with the protective collar advised by the vet if one is prescribed. Discharge around the eye can be wiped gently with a soft pad moistened with lukewarm water. Do not press on the eyeball or rub its surface. Use only suitable eye care materials and prescribed medicines.
Monitor whether your cat opens the eye better, rubs less and develops changes in eye clarity or pupil size. Pain relief alone does not confirm that an ulcer has healed or eye pressure has returned to normal. Staining or pressure measurement may be repeated at follow-up. Treatment should not be stopped on appearance alone.
If pain increases after medication or the eye starts closing again, contact the treating vet. Mention if giving the medicine is not practical too. The approach may need adjusting so the eye receives the treatment it needs.
Prevention
As blepharospasm is a sign, prevention targets underlying diseases:
- protecting your cat from eye injuries,
- regular veterinary checks,
- using hypoallergenic litter and care products,
- infection control and early treatment of eye diseases.
No individual “hypoallergenic” litter has been shown to prevent every feline eye disease. Reducing possible environmental irritants does not replace examination if your cat squints or has persistent watering. In a flat-faced cat, eyelid closure and surface health should also be checked even without obvious pain.
This text provides general information and does not replace veterinary care. If your cat develops symptoms, contact a vet.
Frequently asked questions
Can a squinting cat have an eye ulcer that is not visible?
Yes. Small surface lesions are often detected only through fluorescein staining and careful examination. Marked squinting or keeping an eye closed therefore warrants a prompt veterinary visit even when it looks almost normal externally.
Can I treat a cat's blepharospasm with old eye drops?
Not without veterinary assessment. Different causes need different treatments, and a steroid-containing drop, for example, can be harmful with a corneal ulcer. Even a previously similar-looking symptom may have a different cause this time.
Is blepharospasm contagious?
Involuntary eyelid contraction itself is not contagious. However, the cause may be an infectious eye or respiratory disease, such as herpesvirus, or something entirely different, such as an injury or glaucoma. Any transmission risk is assessed according to the cause.
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
- Corneal Ulcers in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Glaucoma in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Uveitis in Cats, VCA Animal Hospitals, accessed 2026-11-03.
- Eyelids in Animals, Merck Veterinary Manual, accessed 2026-11-03.
- Conjunctivitis, Cornell Feline Health Centre, accessed 2026-11-03.
- Guideline for Feline Herpesvirus Infection, European Advisory Board on Cat Diseases, accessed 2026-11-03.
- Weepy eyes in cats, PDSA, accessed 2026-11-03.
- Understanding Brachycephalic Ocular Syndrome (BOS), American College of Veterinary Ophthalmologists, accessed 2026-11-03.