# Eye Ulcers in Cats: Symptoms, Causes, and Treatment An eye ulcer in cats symptoms can be easy to miss at first, but most owners notice squinting, excessive tearing, or a cat that suddenly avoids bright light. A corneal ulcer is a scratch or open sore on the clear surface of the eye, and it is painful enough that your cat needs to see a veterinarian the same day you suspect one. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - A corneal ulcer is an open sore on the clear front surface of the eye, and it hurts. Cats often hide pain, so squinting and pawing at the face are meaningful clues. - Feline herpesvirus-1 is a leading cause, but foreign objects, eyelid shape problems, and injuries also trigger ulcers [1]. - Your veterinarian confirms an ulcer with a fluorescein dye test, which makes even tiny sores glow under a special light [1]. - Treatment almost always involves prescription topical antibiotics and other eye medications. Never use a leftover or human eye drop on a cat. - Most superficial ulcers heal with consistent at-home treatment and rechecks, but deep ulcers and perforations are emergencies [2]. ## What Is a Corneal Ulcer in Cats? The cornea is the clear dome on the front of your cat's eye. It protects the inner eye and helps focus light onto the retina so your cat can see [1]. When the surface layer of that dome breaks down, the result is a corneal ulcer, also called ulcerative keratitis. Ulcers can be superficial, meaning they only affect the outer layers, or they can go deeper into the stroma, the thick middle layer of the cornea [1]. The deepest and most dangerous category includes descemetoceles and perforations, where the ulcer eats almost through the cornea or punches all the way through [3]. A perforated eye is a surgical emergency. Because the cornea is packed with nerve endings, ulcers are genuinely painful. A cat with an ulcer may feel like it has a piece of sand stuck in its eye that never washes out. That pain is why prompt treatment matters, both for comfort and for saving vision. If you want a broader look at how feline eye problems fit together, see [Feline Ocular Diseases: Common Conditions and Treatment](/knowledge/veterinary-medicine/clinical-methods/feline-ocular-diseases-common-conditions-treatment). ## Cat Eye Ulcer Symptoms: What Owners Notice First The earliest signs are usually about comfort, not appearance. You may not see anything wrong with the eye itself on day one. ### Common signs - Squinting or holding one eye partly or fully closed - Excessive tearing or watery discharge from one eye - Pawing at the eye or rubbing the face against furniture - Sensitivity to light, with your cat turning away from windows or lamps - A cloudy, hazy, or bluish spot on the surface of the eye - Redness in the white of the eye or the eyelids - A swollen, puffy third eyelid sliding across the eye - Eye discharge that changes from clear to yellow or green Chemosis, which is swelling of the conjunctiva, was present in some cats whose ulcers healed slowly in one review of 71 corneal ulcers in 68 cats [4]. If the tissue around your cat's eye looks puffy and swollen, mention it to your veterinarian. ### Signs that mean the eye is getting worse - The eye looks bigger or bulges - The cornea turns dark, brown, or black (this can be a corneal sequestrum) - Blood vessels grow across the clear part of the eye - Your cat stops eating or hides more than usual - The eye starts leaking fluid or looks like it has ruptured A corneal sequestrum is a dead, pigmented patch of cornea that some cats develop after ulceration. In one referral population, sequestra occurred in a meaningful share of cats with ulcerative keratitis, and brachycephalic cats (flat-faced breeds like Persians and Himalayans) were more affected by both ulcers and sequestra [3]. If you notice a dark spot on your cat's eye, that is a same-day call to your veterinarian. ## What Causes Cat Eye Ulcers? Owners often ask what causes cat eye ulcers, and the honest answer is that there are several common pathways. ### Feline herpesvirus-1 Ulcerative keratitis is frequently caused by infection with feline herpesvirus-1 [1]. This virus is extremely common in cats, and after the initial infection it stays in the body for life. It can reactivate during stress, illness, or other immune challenges, producing ulcers that are slow to heal and can recur throughout the cat's life [1]. Secondary bacterial infections are common and can make ulcers worse [1]. ### Physical and anatomical causes Ulcers can also be caused by foreign objects or defects in the shape or form of the eyelids [1]. Examples include: - A plant awn, piece of grit, or other foreign material trapped under the eyelid - Entropion, where the eyelid rolls inward and lashes rub the cornea - Ectopic cilia, which are abnormal hairs growing out of the wrong spot and scraping the eye surface - Trichiasis, where normal hairs point the wrong way and contact the cornea One case report described an eleven-month-old Maine Coon with a chronic history of tearing and eyelid spasms who turned out to have abnormal hairs arising from the third eyelid, along with eyelid entropion and non-ulcerative keratitis [5]. That case shows how a structural problem can keep irritating an eye until it is corrected. ### Other risk factors - Brachycephalic anatomy. Flat-faced cats had a much higher prevalence of ulcerative keratitis than cats with normal skull shapes in a referral population (36% versus 15%) [3]. - Anesthesia and reduced tear production. In a study of 42 cats undergoing general anesthesia for non-eye procedures, tear production dropped significantly for at least four hours after anesthesia, and 23 of the eyes (27.4%) developed corneal erosion despite prophylactic lubrication [6]. If your cat has surgery, ask your veterinarian about eye protection and post-anesthetic eye checks. - Trauma. Scratches from another cat, a swipe from a claw, or a run-in with a sharp object can all injure the cornea. ## How Veterinarians Diagnose a Corneal Ulcer Diagnosis usually happens in one visit and does not require sedation in most cats. Your veterinarian starts with a full eye exam, checking eyelid position, tear production, and the surface of the eye. To detect small ulcers, they may put drops of a specialized dye into the eye [1]. This fluorescein dye sticks to damaged cornea and glows green under a blue light, which makes even a tiny scratch visible. Your veterinarian may also: - Measure tear production with a Schirmer tear test - Check the eyelids closely for inward-rolling lids or abnormal hairs - Look for a corneal sequestrum, a dark patch of dead corneal tissue - Assess how deep the ulcer goes, since depth changes the treatment plan - Swab or culture the eye if infection is suspected Ulcers are often graded by depth. Superficial ulcers involve only the outer layers, stromal ulcers reach the middle layer, and the most severe grade includes descemetoceles and perforations [3]. That grading drives everything that follows, from medication choice to whether surgery is needed. ## Treatment Options for Cat Eye Ulcers Treatment depends on how deep the ulcer is, what caused it, and whether infection is involved. ### Medical treatment Initial therapy is removal of the dead, damaged, or infected tissue of the ulcer by your veterinarian, followed by topical antibiotics and other prescription medication [1]. In practice, that often means: - Prescription antibiotic eye drops or ointment, sometimes several times a day - Antiviral medication if feline herpesvirus-1 is suspected - Pain relief, which your veterinarian will select and dose based on your cat's weight and health - An Elizabethan collar (cone) to stop your cat from rubbing the eye Never reach for a leftover antibiotic or a human eye drop. Some human drops contain steroids, which can worsen certain ulcers, and some contain preservatives that irritate a damaged cornea. ### Procedures and surgery For resistant cases, there are surgical procedures to stimulate the replacement or development of new corneal tissue, although there are a few risks with these procedures [1]. Your veterinarian can advise you regarding the best treatment for your cat [1]. Newer options exist for the toughest cases. In a retrospective study of 24 cats with deep corneal ulcers or perforations, 15 of 17 cats (88%) treated with subconjunctival mesenchymal stem cell injections became fluorescein-negative within one to three weeks, compared with a slower course in the remaining cats [2]. This is a specialized treatment offered at some referral practices, not a first-line home remedy. ### What to expect at home - Give every dose on schedule. Skipping doses is one of the most common reasons ulcers stall. - Keep the cone on until your veterinarian says to remove it. - Do not let your cat rub its face on carpet, furniture, or other pets. - Return for every recheck, even if the eye looks better. If your cat also has discharge without an obvious ulcer, [Cat Eye Discharge: Causes and When to See a Vet](/knowledge/veterinary-medicine/online-vet-and-care-costs/cat-eye-discharge-causes-when-to-see-vet) covers the common patterns. ## Recovery, Outlook, and Long-Term Management Most superficial ulcers improve within days of starting treatment, but healing times vary widely. In one review, delayed healing occurred in 8 of 71 ulcers (11.3%), corneal sequestration in 20 of 71 (28.2%), and corneal stromal vascularization after healing in 9 of 71 (12.7%) [4]. Those numbers are a reminder that some ulcers need patience and repeated rechecks. That same review found that delayed healing was significantly more likely when chemosis was present at the first visit, or when treatment included oral lysine, topical nonsteroidal anti-inflammatory drugs, or topical EDTA [4]. If your cat is on one of those medications and the ulcer is not improving, ask your veterinarian whether the plan should change. | Finding | What it means for your cat | |---|---| | Superficial ulcer | Often heals with topical medication and rechecks | | Stromal ulcer | Deeper damage, may need more intensive treatment or surgery | | Descemetoceles or perforation | Emergency, surgery often required [3] | | Corneal sequestrum | Dark dead tissue, may need surgical removal [3] | | Slow healing | Recheck schedule may be extended, treatment adjusted [4] | Cats with herpesvirus-related ulcers may have flare-ups for life [1]. Long-term management often includes reducing stress, keeping up with routine veterinary visits, and treating new episodes early. Some cats need long-term antiviral or immune-supporting therapy chosen by their veterinarian. If your cat has a non-healing sore on the lip or skin instead of the eye, that is a different problem. See [How To Treat Rodent Ulcers In Cats](/knowledge/veterinary-medicine/clinical-methods/how-to-treat-rodent-ulcers-in-cats). ## Prevention You cannot prevent every ulcer, but you can lower the odds. - Treat eyelid problems early. Entropion, trichiasis, and ectopic cilia keep damaging the cornea until they are fixed [1][5]. - Manage herpesvirus triggers. Stress, boarding, and new pets can set off flare-ups in carrier cats [1]. - Use caution with other cats. Claw scratches are a common cause of corneal injury. - Ask about eye protection during anesthesia. Tear production drops after general anesthesia, and corneal erosion occurred in 27.4% of eyes in one study despite lubrication [6]. - Keep up with wellness exams. Your veterinarian can spot eyelid and tear film problems before an ulcer forms. For a wider look at keeping feline eyes healthy, see [Cat Eyes: Understanding Feline Vision, Common Eye Problems & Care Tips](/knowledge/veterinary-medicine/symptom-guides/cat-eyes-anatomy-health). ## Limitations and When to Contact a Veterinarian This article cannot tell you whether your cat has an ulcer, how deep it is, or which medication is safe. Only a veterinarian who examines your cat can do that, and individual cases always need professional assessment. Call your veterinarian the same day if you see: - Squinting that lasts more than a few hours - A cloudy, blue, or dark spot on the eye - Tearing or discharge from one eye - Pawing at the face or rubbing the eye - A known scratch or injury to the eye Go to an emergency clinic right away if: - The eye looks like it has ruptured or is leaking fluid - The eyeball is bulging or the eye is suddenly much larger - Your cat is in obvious severe pain, crying, or cannot open the eye at all - There is bleeding from the eye - Your cat stops eating or becomes lethargic along with the eye problem Schedule a routine visit if your cat has a history of herpesvirus-related eye problems and you want to discuss a long-term management plan. If you are unsure whether an eye issue is urgent, call your veterinary clinic and describe what you see. They would rather hear from you early than see a perforated eye later. ## Frequently Asked Questions ### Can a cat eye ulcer heal on its own? Small superficial ulcers sometimes heal without treatment, but you cannot tell depth or infection risk by looking at the eye. Untreated ulcers can deepen, become infected, or perforate, so same-day veterinary care is the safer choice. ### Is a corneal ulcer in cats contagious to other pets? The ulcer itself is not contagious, but feline herpesvirus-1, a common underlying cause, spreads between cats through sneezing, saliva, and shared food or water bowls. Keep a cat with an active eye problem separated from other cats until your veterinarian clears it. ### How long does it take for a cat eye ulcer to heal? Many superficial ulcers improve within several days of starting treatment, but healing time depends on depth, cause, and how consistently you give medications. Some cats take weeks, and a small share of ulcers heal slowly enough that the treatment plan needs adjusting. ### Can I use human eye drops on my cat? No. Human eye drops may contain steroids, preservatives, or other ingredients that can worsen a corneal ulcer or delay healing. Use only medications your veterinarian prescribes for your cat, and ask before adding anything else. ### Will my cat's vision be affected after an ulcer? Many cats recover good vision after a superficial ulcer heals, especially with prompt treatment. Deep ulcers, perforations, and corneal sequestra can leave scarring that reduces vision, and some eyes require surgery to preserve both comfort and sight. ## Related Articles - [Feline Ocular Diseases: Common Conditions and Treatment](/knowledge/veterinary-medicine/clinical-methods/feline-ocular-diseases-common-conditions-treatment) - [Cat Eye Discharge: Causes and When to See a Vet](/knowledge/veterinary-medicine/online-vet-and-care-costs/cat-eye-discharge-causes-when-to-see-vet) - [How To Treat Rodent Ulcers In Cats](/knowledge/veterinary-medicine/clinical-methods/how-to-treat-rodent-ulcers-in-cats) - [Cat Eyes: Understanding Feline Vision, Common Eye Problems & Care Tips](/knowledge/veterinary-medicine/symptom-guides/cat-eyes-anatomy-health) - [Symptoms Of Urinary Infection Cats](/knowledge/veterinary-medicine/symptom-guides/symptoms-of-urinary-infection-cats) - [What Are Symptoms Of A Uti In A Cat](/knowledge/veterinary-medicine/symptom-guides/what-are-symptoms-of-a-uti-in-a-cat) - [Corneal Ulcer in Cats: Symptoms and Healing Time](/knowledge/veterinary-medicine/symptom-guides/corneal-ulcer-in-cats) - [Uveitis in Cats: Causes, Symptoms, and Treatment](/knowledge/veterinary-medicine/symptom-guides/uveitis-cats-causes-symptoms-treatment) - [Eye Mucus in Cats: Causes and When to See a Vet](/knowledge/veterinary-medicine/symptom-guides/eye-mucus-in-cats) ## References 1. [Disorders of the Cornea in Cats - Cat Owners](https://www.merckvetmanual.com/cat-owners/eye-disorders-of-cats/disorders-of-the-cornea-in-cats). Merck Veterinary Manual. 2. [Efficacy of mesenchymal stem cell therapy for treating deep corneal ulcers and corneal perforation in cats: a retrospective study](https://pubmed.ncbi.nlm.nih.gov/41622128/). Journal of feline medicine and surgery, 2026. 3. [Prevalence and Characteristics of Feline Ulcerative Keratitis and Corneal Sequestra in a Referral Population and Comparison Between Brachycephalic and Nonbrachycephalic Cats](https://pubmed.ncbi.nlm.nih.gov/40739742/). Veterinary ophthalmology, 2026. 4. [Spontaneous Superficial Ulcerative Keratitis in Client-Owned Cats: Risk Factors for Delayed Healing, Corneal Sequestration, or Corneal Stromal Vascularization](https://pubmed.ncbi.nlm.nih.gov/42669856/). Veterinary ophthalmology, 2026. 5. [Bilateral Third Eyelid Ectopic Cilia in a Maine Coon Cat](https://pubmed.ncbi.nlm.nih.gov/42768449/). Veterinary ophthalmology, 2026. 6. [Impact of general anesthesia on feline aqueous tear production and the feline corneal epithelium](https://pubmed.ncbi.nlm.nih.gov/41024328/). Journal of feline medicine and surgery, 2025. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners) - [Cornell Feline Health Center: Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information)