Cat Squinting: Causes, Step-by-Step Management, and Signs It’s Time to Visit the Vet

Eye HealthSymptomsMeongsiljang Veterinary Advisory Board

A cat squinting its eyes shouldn’t be ignored—it could lead to blindness. Here’s a step-by-step guide to understanding the causes, such as herpesvirus, corneal ulcers, and glaucoma, along with how to address each one and when it’s time to visit the vet.

If Your Cat Is Squinting — Check the Urgency Level First

Squinting in cats is a symptom where they cannot fully open their eyelids due to pain, irritation, or inflammation, resulting in half-open or closed eyes. The key to management lies in how quickly you can identify the underlying cause. As noted in veterinary ophthalmology textbooks, feline herpesvirus (FHV-1) is frequently implicated in various eye diseases, highlighting the diverse range of potential causes for squinting. Cats in pain often squint by raising the third eyelid (nictitating membrane) inside the eye. Some conditions, such as corneal ulcers, can lead to corneal damage or blindness if left untreated. Therefore, it is essential to first check whether one or both eyes are affected and whether there is accompanying discharge or redness.

4 Stages of Squinting Urgency — Do You Need to Go to the Vet Now?

Please use the table below to assess your pet’s condition.

Stage	Symptoms	Action
Stage 1 (Observation)	Occasional eye rubbing, slight tearing	Observe for 1–2 days; visit a vet if symptoms persist
Stage 2 (Caution)	Persistent squinting, accompanied by discharge or redness	Visit a vet within 24 hours
Stage 3 (Severe)	Eyes completely closed, light avoidance, white spots on the cornea	Visit a vet the same day
Stage 4 (Emergency)	Proptosis or enophthalmos, excessive discharge, severe pain	Visit an emergency animal hospital immediately

Checklist of Accompanying Symptoms — Signs to Identify the Cause

Excessive tearing and discharge: If your pet’s eyes are watering excessively or producing yellow or green discharge, suspect a bacterial infection or herpesvirus.

Redness: Redness in the whites of the eyes may indicate conjunctivitis or uveitis.

Light avoidance: Squinting more in bright light can signal pain from corneal damage or uveitis.

White changes in the cornea: A cloudy cornea or white spots suggest a corneal ulcer. Immediate veterinary care is needed.

Third eyelid protrusion: If a white membrane rises from the inner corner of the eye, it may indicate severe pain or a systemic illness.

A close-up of a cat's eye showing redness and protrusion of the third eyelid.

Signs You Need to Go to an Emergency Animal Hospital Immediately

If you notice any of the following symptoms, your cat needs emergency care today: the eye bulging or sinking in, the entire cornea becoming cloudy, blood or a large amount of pus-like discharge coming from the eye, or the cat refusing food while keeping the eye completely closed. Contact an emergency veterinary clinic immediately. A cat's eye condition can deteriorate rapidly within just a few hours.

7 Main Causes of Cat Squinting

Feline Herpesvirus (FHV-1): This is a very common cause. The virus can remain latent in the body and reactivate when the immune system is compromised due to stress or other factors. Corneal Ulcer: This causes severe pain. If left untreated, deep ulcers can lead to corneal perforation and blindness. Uveitis: This is inflammation of the inner structures of the eye (the iris and ciliary body). It is often associated with systemic diseases such as toxoplasmosis, bartonellosis, feline infectious peritonitis (FIP), or tumors, so a comprehensive systemic examination is essential. Conjunctivitis: This is inflammation of the conjunctiva, typically accompanied by ocular discharge and redness. Glaucoma: Increased intraocular pressure can lead to blindness. Trauma or Foreign Bodies: This includes injuries from scratches (e.g., from claws) or the presence of foreign objects, such as plant material, in the eye. Intraocular Tumors: Tumors inside the eye, such as lymphoma or iris melanoma, can also be the underlying cause.

Treatment by Cause — Why You Can’t Just Wait at Home

Herpesvirus is managed with antiviral eye drops, and broad-spectrum antibiotic eye drops are often used concurrently to prevent secondary bacterial infections. Artificial tears to supplement the tear film can also be helpful. However, steroid eye drops should never be used indiscriminately on eyes suspected of having FHV-1. All corneal ulcers are treated with antibiotic eye drops; deep or melting ulcers require fluoroquinolone eye drops and systemic antibiotics, and in severe cases, surgery is necessary. Uveitis is treated with anti-inflammatory (steroid) eye drops, but underlying causes must also be investigated. Glaucoma requires immediate treatment to lower intraocular pressure and may lead to surgery. For all causes, waiting at home without a diagnosis can result in missing the window for effective treatment.

First Aid You Can Do at Home Before Visiting the Vet

To prevent your cat’s eye condition from worsening before the vet visit, follow these care steps. First, fit an Elizabethan collar to stop them from rubbing their eyes with their paws. Second, gently wipe away discharge around the eyes using sterile saline solution; do not use cotton swabs. Third, never apply human eye drops or ointments. Fourth, dim the lighting to reduce light irritation. These are temporary measures only—definitive treatment for the underlying cause must be performed at a veterinary clinic.

Pay Special Attention to Senior Cats and White Cats

Cats are skilled at hiding pain. Even a slight squint may indicate severe discomfort, and they may raise their third eyelid (nictitating membrane) when in pain. In senior cats, systemic conditions such as hypertension can manifest as ocular symptoms like retinal detachment or hemorrhage, so extra vigilance is warranted. Additionally, white or light-colored cats are prone to skin diseases and tumors on areas with less pigmentation, such as the eyelids, making it important to limit their sun exposure. If symptoms persist for more than 48 hours, even if they seem mild, please visit the clinic.

Preventive Care for Cat Eye Health

Stress is a common trigger for herpesvirus flare-ups, so managing stress is especially important around times of change, such as introducing a new cat, moving, or visiting the vet. Regular eye exams once or twice a year can help catch any issues early. Keeping your cat indoors significantly reduces the risk of injury and infection. In multi-cat households, separate food and water bowls to prevent the spread of conjunctivitis. Gently wiping around the eyes with a damp gauze pad two to three times a week can help prevent discharge and irritation.

A caregiver gently wiping around a cat’s eyes.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

My cat is squinting with only one eye. Could something have gotten into it?

While a foreign object could be the cause, conditions like herpesvirus, corneal ulcers, and conjunctivitis also often start in one eye. Avoid touching the eye directly; instead, gently rinse it with sterile saline. If there is no improvement within an hour, please visit a veterinary clinic.

It seems the squinting has resolved on its own. Is it okay to just leave it alone?

Corneal ulcers and herpesvirus infections may appear to improve temporarily, but they can recur or worsen. If symptoms return within 24 to 48 hours, your pet must be seen by a veterinarian.

Can I use human eye drops on my cat?

Absolutely not. Preservatives and other ingredients in human eye drops can be toxic to cats. Always use only animal-specific eye drops prescribed by a veterinarian.

How can you tell the difference between a cat squinting its eyes and glaucoma?

Glaucoma can cause the eye to appear progressively enlarged (buphthalmos) and red due to increased intraocular pressure. However, secondary glaucoma in cats may not present with obvious signs of pain, making it difficult to identify based on appearance alone. An accurate diagnosis requires intraocular pressure measurement at a veterinary clinic.

My pet is squinting a lot—can we wait until tomorrow’s appointment?

If you notice white spots on the cornea, if your pet keeps its eyes tightly shut and is extremely sensitive to light, or if there is excessive discharge, do not wait until the next day—seek emergency veterinary care immediately.

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References

[1] Reinstein S. The squinting cat: Herpes until proven otherwise. In: Englar RE, ed. The Veterinary Workbook of Small Animal Clinical Cases. Sheffield: 5M Publishing; 2020.

[2] Colitz CM. Feline uveitis: diagnosis and treatment. Clin Tech Small Anim Pract. 2005;20(2):117–120.

[3] Blocker T, van der Woerdt A. The feline glaucomas: 82 cases (1995–1999). Vet Ophthalmol. 2001;4(2):81–85.

[4] Lim CC, Maggs DJ. Ophthalmology. In: Little SE, ed. The Cat: Clinical Medicine and Management. 2nd ed. St. Louis, MO: Saunders Elsevier; 2012:807–845.

[5] Silverstein SM, Hopper K, eds. Feline Emergency and Critical Care Medicine. 2nd ed. Ames, IA: Wiley-Blackwell; 2015.