Why Cat Eye Problems Are Easy to Miss
Cats are instinctively inclined to conceal signs of pain and illness, a behaviour rooted in their nature as both predators and prey. This means that by the time an eye problem becomes visibly obvious to an owner, the condition may already be well established. Unlike dogs, who may paw at a sore eye or whimper, cats often simply become quieter or slightly less active — changes that owners can easily attribute to normal variation. Understanding the signs and conditions that commonly affect feline eyes allows you to act sooner and protect your cat's vision.
Common Eye Conditions in Cats
Conjunctivitis
Conjunctivitis — inflammation of the conjunctiva — is the most frequently seen eye condition in cats. Unlike in dogs, conjunctivitis in cats is usually infectious in origin. Feline herpesvirus type 1 (FHV-1) is the single most common cause and is responsible for a significant proportion of cases, particularly in kittens and younger cats. Bacterial causes, especially Chlamydophila felis and Mycoplasma felis, are also common.
Feline Herpesvirus (FHV-1)
FHV-1 is a highly prevalent virus in the cat population. Most cats are exposed in kittenhood, often during the first bout of cat flu, and once infected the virus remains latent in the trigeminal nerve ganglion for life. Stress is the most common trigger for reactivation — rehoming, the arrival of a new pet, illness, or surgery can all precipitate a flare. During reactivation, the cat sheds the virus and typically develops conjunctivitis, which may be accompanied by an upper respiratory infection. Antiviral treatment with famciclovir (given orally) is effective for severe flares. L-lysine supplements were once widely recommended to suppress FHV-1 replication, but current evidence does not support their routine use, and the World Small Animal Veterinary Association (WSAVA) no longer recommends them.
Chlamydiosis
Chlamydophila felis causes a distinctive bacterial conjunctivitis that often begins in one eye before spreading to the other. It is one of the more treatable causes, responding well to systemic doxycycline. There is a zoonotic risk — humans can acquire Chlamydophila felis, although transmission is uncommon and disease in immunocompetent individuals tends to be mild. Vaccination against Chlamydophila felis is available in the UK as part of some polyvalent vaccines and may be recommended for cats in multi-cat environments.
Corneal Ulcers
Corneal ulcers in cats are often caused by FHV-1, which can infect the corneal cells directly, leading to characteristic dendritic (branching) ulcers visible with fluorescein staining. They may also result from trauma or foreign bodies. Corneal ulcers are painful and the cat may squint heavily, hold the eye closed, or show increased sensitivity to light. Untreated ulcers risk infection and perforation of the eye.
Uveitis
Uveitis — inflammation of the internal eye structures — tends to be more serious in cats than in dogs because it is frequently associated with systemic infectious disease. FIV (feline immunodeficiency virus), FeLV (feline leukaemia virus), toxoplasmosis, and fungal infections are all recognised causes. Uveitis causes a painful, cloudy eye and can lead to cataracts, glaucoma, and blindness if not treated. In cats, uveitis warrants investigation for underlying systemic disease, not just local eye treatment.
Cataracts
Cataracts are less common in cats than in dogs. When they do occur, they are often secondary to another condition such as uveitis or metabolic disease, rather than being primary inherited conditions. A cat with a cloudy lens should be assessed to identify the underlying cause.
Hypertensive Retinopathy
High blood pressure (systemic hypertension) is a significant cause of sudden blindness in cats, particularly older cats with chronic kidney disease (CKD) or hyperthyroidism — both of which are common feline conditions. Elevated blood pressure damages the delicate blood vessels of the retina, which can lead to retinal haemorrhage or detachment and rapid, severe vision loss. Owners may notice dilated pupils that do not respond to light, apparent disorientation, or the cat suddenly walking into objects.
Third Eyelid Protrusion
Protrusion of the third eyelid (nictitating membrane) in one or both eyes is a non-specific sign that something is wrong. In cats, it can indicate local eye pain or irritation, but it can also be a sign of systemic illness, gastrointestinal disease, or significant weight loss. A cat with a visible third eyelid always warrants a veterinary assessment.
Recognising Squinting as a Key Warning Sign
Blepharospasm — the medical term for squinting or involuntary partial eye closure — is one of the most important signs of a painful eye in any animal. A cat holding an eye even slightly more closed than usual, or keeping it partially shut, is almost certainly experiencing discomfort. This should not be ignored or attributed to tiredness. Any squinting that is persistent or accompanied by discharge should prompt a vet call.
Sudden Blindness in Cats: Act Within Hours
If your cat appears to have lost vision suddenly — dilated pupils that do not react to light, walking into furniture, appearing confused or fearful — the most likely cause in a middle-aged or older cat is hypertensive retinopathy from uncontrolled high blood pressure. This is a genuine emergency. Treatment to reduce blood pressure, if started within hours of retinal detachment, can sometimes restore partial or even full vision. Every hour of delay reduces the likelihood of recovery. Measure blood pressure and begin treatment at an emergency vet immediately.
Breed Predispositions
Persian and Exotic Shorthair cats, with their flat faces and prominent eyes, are prone to entropion (inward rolling eyelid), persistent epiphora (tear overflow causing facial staining), and corneal exposure problems similar to those seen in brachycephalic dog breeds. Siamese cats have an increased incidence of strabismus (crossed eyes), which is usually congenital and cosmetic rather than vision-threatening. Burmese cats carry a higher risk of primary glaucoma, and affected individuals should be regularly monitored.
Urgent Signs Requiring Immediate Veterinary Attention
- Sudden loss of vision or apparent blindness — check blood pressure urgently
- A bulging eye or eye that appears displaced from the socket (proptosis) — this requires emergency surgery
- Signs of corneal perforation — a dark spot or visible inner contents of the eye
- Persistent squinting with marked discharge, especially if the cat is not eating normally
- Any eye injury from trauma or a sharp object
What Not to Do
Never apply dog eye drops or ointments to a cat's eyes. Some formulations contain ingredients that are safe for dogs but toxic to cats — this is particularly relevant for products containing certain preservatives or active ingredients that cats metabolise differently. Always obtain a product specifically licensed or recommended by your vet for feline use.
Avoid trying to remove a foreign body from the eye yourself. What appears to be a piece of grit may be a deeper foreign body or an area of corneal ulceration that looks similar. Attempting removal risks further injury. Clean gently around the eye with sterile saline and seek veterinary advice.
When to Call Your Vet
Because cats mask discomfort so effectively, the threshold for contacting your vet about an eye problem should be lower than it might be for a dog showing more obvious signs of pain. Any eye discharge that persists beyond a day, any squinting, third eyelid protrusion, or change in eye appearance warrants a call. Early treatment is almost always more effective and less expensive than treating an established or complicated condition.