Seeing one of your cat’s eyes turn red, watery, swollen, or painful can be worrying. Sometimes the cause is simple irritation. Other times, redness is related to infection, injury, inflammation, glaucoma, or another condition that should be examined by a veterinarian.
York Veterinary Hospital treats cats with eye redness, discharge, swelling, squinting, and sudden changes in comfort. Since many eye conditions look similar from the outside, guessing at the cause can be risky. An eye exam helps identify what is happening and what treatment is safest. This guide covers common causes of red eyes in cats, warning signs, diagnostic steps, treatment options, and situations that need prompt care.
Common Causes of Red Eyes in Cats
A cat’s eye may look red because of irritation on the surface, swelling around the eyelids, or inflammation deeper inside the eye. Some causes are mild. Others may become painful or affect vision when care is delayed.
Conjunctivitis
Conjunctivitis occurs when the conjunctiva becomes inflamed. The conjunctiva is the thin tissue lining the inner eyelids and part of the eye surface. In cats, this inflammation may be linked to a virus, bacteria, irritants, or another inflammatory cause.
Signs can include redness, puffiness around the eye, discharge, squinting, frequent blinking, or rubbing the face.
Eye Infections
Viruses and bacteria can both cause eye infections in cats. Fungal eye infections are less common. Feline herpesvirus is a common reason cats develop recurring eye and upper respiratory signs. Once exposed, many cats carry the virus long-term, and flare-ups may happen during periods of stress.
An infection may cause redness along with discharge, squinting, swollen eyelids, sneezing, or lower energy.
Allergies and Irritants
Dust, pollen, smoke, cleaning products, fragrances, and other airborne irritants can leave a cat’s eyes red or watery. Some cats also develop puffiness near the eye. A veterinary exam can help separate simple irritation from allergy, infection, injury, or another eye disease.
Eye Injuries or Trauma
Cats may injure an eye during rough play, a fight with another animal, contact with a plant, or an accidental bump at home. A small corneal scratch can still be painful and may worsen without care.
Book an exam if you think your cat may have an eye injury, especially if they are squinting, rubbing the eye, or keeping it partly or fully closed.
Glaucoma
Glaucoma develops when pressure inside the eye rises too high. Increased pressure can damage sensitive eye structures and may lead to vision loss. Possible signs include redness, cloudiness, a larger pupil, swelling, pain, or an eye that appears enlarged.
Glaucoma needs urgent veterinary care. The sooner pressure is addressed, the better the chance of protecting comfort and reducing the risk of lasting damage.
Uveitis
Uveitis is inflammation within the eye, often involving the iris and other internal structures. It can be painful and may be connected to infection, trauma, immune-mediated disease, or another medical problem.
This is not the same as a mild surface irritation. A veterinarian needs to diagnose the cause before choosing treatment.
Foreign Objects in the Eye
Dust, hair, plant material, tiny seeds, or other debris can become trapped near the eye. This may cause redness, tearing, blinking, squinting, or pawing. Cats with outdoor access may be exposed to this more often.
Do not try to remove anything that appears stuck in or on the eye. A veterinarian can check the eye safely with the right equipment.
Signs and Symptoms to Watch For
Redness matters, but the other signs around it help show how urgent the problem may be.
Redness in One or Both Eyes
Redness may appear in the white of the eye, the eyelids, or the tissue around the eye. One red eye may be due to trauma, debris, or a localized problem. Redness in both eyes may suggest infection, irritation, allergy, or a broader health issue.
Swelling or Discharge
Swelling may affect the eyelids, the tissue around the eye, or the eye itself. Discharge may be clear and watery, thick, yellow, green, or blood-tinged. Your veterinarian will use the type and amount of discharge, along with the exam findings, to decide what testing or treatment is needed.
Squinting or Pawing at the Eye
Squinting, repeated blinking, keeping the eye closed, and rubbing at the eye are all signs of discomfort. Rubbing may also cause additional irritation or injury.
Cloudiness or Changes in Vision
A cloudy-looking eye surface, a sudden pupil change, bumping into objects, or moving more cautiously can point to a more serious eye problem. These signs should be assessed quickly.
Changes in Mood, Appetite, or Hiding
Eye pain can affect a cat’s behavior. Your cat may hide, become irritable, play less, eat less, groom less, or pull away when touched near the face. Tell your veterinarian about any behavior changes that are unusual for your cat.
Diagnosis by a Veterinarian
When your cat is seen at York Veterinary Hospital for a red eye, our veterinary team examines the eye closely and checks for the cause of the redness.
Physical Eye Examination
The veterinarian will assess the eye, eyelids, surrounding tissue, pupils, cornea, discharge, swelling, and comfort level. A bright exam light and magnification can make subtle eye changes easier to see.
Testing for Infection or Underlying Conditions
If infection or another medical concern is possible, your veterinarian may recommend additional testing. This may include checking discharge, assessing whether viral or bacterial causes are likely, or looking for signs that another health issue is affecting the eye.
Measuring Eye Pressure
Your veterinarian may use a tonometer to measure pressure inside the eye. This helps check for glaucoma and other pressure-related problems. The test is quick and is often part of a complete eye assessment.
Fluorescein Dye Testing
Fluorescein stain helps detect corneal scratches, ulcers, or surface defects. A small amount of stain is placed on the eye, then the cornea is checked with a special light to make damaged areas easier to identify.
Treatment Options
Treatment depends on the cause. Because many eye conditions look alike at home, medication should be chosen after a veterinary exam.
Prescription Eye Drops or Ointments
If your cat has an infection, inflammation, or a corneal problem, your veterinarian may prescribe eye drops or ointment. Give the medication exactly as directed, and continue for the full recommended course unless your veterinarian changes the plan.
Anti-Inflammatory Medication
Some cats need medication to calm inflammation and ease discomfort. The right medication depends on the diagnosis. Some eye drops are unsafe when a corneal ulcer is present, so do not use leftover medication from another pet.
Pain Relief
Eye pain can be significant. If your cat seems uncomfortable, your veterinarian may prescribe pain medication or other supportive treatment.
Surgery or Advanced Treatment
Severe glaucoma, deep corneal ulcers, serious trauma, or long-term painful eye disease may need advanced care, surgery, or referral. In some cases, the goal is to protect vision. In others, the priority is pain control and preventing further injury.
Home Care to Support Treatment
Home care should follow the veterinary plan.
- Gently wipe discharge with a clean, damp cloth if your cat allows it.
- Use an Elizabethan collar if your veterinarian recommends one.
- Keep your cat in a quiet, comfortable room during recovery.
- Give all medications as prescribed.
- Call your veterinarian if symptoms worsen or medication becomes difficult to give.
Preventive Measures
You cannot prevent every eye problem, but you can reduce some risks.
- Keep cats indoors, or use supervised outdoor access, to reduce fights and eye injuries.
- Limit exposure to smoke, harsh cleaners, strong fragrances, and airborne irritants.
- Keep your cat’s living area clean and allow good airflow.
- Book regular veterinary check-ups so eye changes can be caught early.
- Keep vaccines up to date, especially for cats at risk of infectious respiratory disease.
When to Seek Immediate Veterinary Help
Call a veterinarian promptly if your cat has a red eye with any of these signs:
- Swelling that does not improve
- Squinting, rubbing, or signs of pain
- Thick yellow, green, or bloody discharge
- Cloudiness on the eye surface
- Sudden vision changes
- A visible scratch, wound, or trauma
- An eye that looks enlarged or bulging
- One pupil looks different from the other
- Redness with lethargy, appetite loss, or other signs of illness
Eye problems can change quickly, and some conditions can affect vision. If your cat has a red eye and you are not sure how serious it is, call a veterinarian rather than waiting.
A red eye in a cat may be linked to irritation, infection, injury, inflammation, glaucoma, or another medical problem. An early exam helps protect comfort, identify the cause, and guide the right treatment.
If your cat has eye redness, swelling, pain, cloudiness, discharge, or a sudden vision change, contact York Veterinary Hospital. Our team can examine your cat’s eye and recommend the safest next step.