What are Eye Infections in Cats?
What is it?
How is it Treated?
Breed Predispositions
Persian cats, Himalayan cats, and other brachycephalic breeds
Introduction
One sunny afternoon, Sarah noticed her usually spirited Siamese cat, Whiskers, had become unusually reserved and had watery eyes with a greenish discharge. Worried about Whiskers’ well-being, she scheduled a visit to their trusted veterinarian for an evaluation. The veterinarian examined Whiskers and diagnosed him with an eye infection—a common but potentially serious issue that can affect cats of all breeds and ages.
Eye infections in cats are common. They can occur due to viral or bacterial infections. Viral infections are typically spread through direct contact with infected animals or fomites. Bacteria can enter the eyes through tears or mucous membranes.
Cats usually develop eye infections due to poor hygiene habits. They lick themselves excessively, resulting in bacterial growth on their tongue and teeth. It is common among cats, especially older ones. However, young kittens and adult cats are also susceptible to this problem.
When a cat gets a severe eye infection, the first thing that happens is that the eyelids close over the affected eye. Next, the cat rubs its face against something that irritates the eye, causing swelling and redness. Next, the conjunctiva becomes inflamed, which makes the cornea swell. Finally, pus forms under the swollen cornea. This is why washing your hands after handling raw meat or petting an animal is essential. Also, try to avoid touching your eyes.

There are two types of eye infections in felines: viral and bacterial. Viral eye infections are typically mild and self-limiting. They tend to last less than ten days. At the same time, the bacterial infection needs antibiotics to heal.
- Viral eye infections. These viruses are spread through direct contact with infected animals or indirectly via contaminated items such as toys, food bowls, bedding, etc. These viruses are typically mild and self-limiting. They tend to last for only a few days. However, sometimes they can become chronic and lead to other problems.
- Bacterial eye infections are microscopic bacterial organisms that live everywhere in nature. Some bacteria are beneficial, while others are harmful. For example, some cats carry certain kinds of bacteria in their eyes without showing signs of infection. This is called the ocular carriage.
Causes of Cat Eye Infections
Bacteria, viruses, parasites, or trauma usually cause eye infections in our feline friends. The most common cause is bacterial conjunctivitis (pink eye). It has been estimated that approximately 10 percent of cats housed in tiny group homes are infected, whereas up to 90 percent of those housed in the larger group.
- Bacterial conjunctivitis is contagious and spreads quickly through direct contact between animals or indirect contact via contaminated items. Bacteria enter the eyes when the eyelids rub against each other during grooming or playing.
- Viral conjunctivitis is an inflammation of the mucous membranes lining the eyelids and inner corners of the eye. It is caused by viruses such as adenovirus, herpes simplex virus (HSV), varicella-zoster virus (VZV), and cytomegalovirus (CMV). The most common cause of viral conjunctivitis is HSV infection. However, about half of them will get rid of the virus now and then, usually under stress. Other causes include bacterial infections, allergic reactions, trauma, chemical irritants, and exposure to smoke, dust, pollen, chemicals, radiation, or drugs.
- Traumatic conjunctivitis is a disease caused by eye trauma, which causes conjunctiva inflammation. It usually occurs after injury to the eye, such as from a foreign body, chemical burns, or blunt force trauma. The most common symptoms include redness, swelling, itching, tearing, pain, blurred vision, and eye discharge.
- Parasitic conjunctivitis is a disease caused by parasites (such as pinworms) living in your cat’s eyes. It causes irritation, itching, redness, swelling, eye discharge, and sometimes pain. In addition, approximately 4 percent of all cats carry Toxoplasma gondii, an organism that causes toxoplasmosis. The symptoms usually go away after treatment.
Symptoms of Eye Infections in Cats
Cat eyes are usually infected by bacteria called styes. Depending on where they occur, symptoms may be different. The first clinical sign that your cat has an eye infection is usually a behavior change.
Your cat might scratch at his eyes more than usual, rub his face on furniture or other objects, or lick his nose excessively. He could also have trouble seeing well. About 20 percent of cats with upper respiratory disease and three percent of normal-appearing cats test positive for C. felis.
Other common signs and symptoms of an eye infection in cats include:
- redness
- pain
- discharge
- swelling
- sensitivity to light.
If you notice these clinical signs, consult your veterinarian immediately. Your vet may be able to treat your cat’s eye infection at home. However, if your cat’s eyes become infected, he may need surgery to remove the affected tissue.
Diagnosis of Eye Infections in Cats
To diagnose feline ocular disease, your vet must perform a complete physical examination, including a thorough slit lamp examination. This includes evaluating the eyes’ external appearance, eyelids, conjunctiva, cornea, iris, lens, vitreous body, retina, optic nerve, fundus, and extraocular muscles.
- Slit Lamp Examination – During this procedure, the veterinarian shines light through the pupil of the cat’s eye and looks at the back of the eyeball. They may also examine the eyelids, tear ducts, cornea, iris, lens, and retina.
- Cytology – This test involves taking a sample of cells from the affected eye area. Cytology is used to determine whether the condition is bacterial or viral.
- Histopathology – This is (also known as histological pathology) the study of tissue sections under a microscope to diagnose disease. It is used in clinical medicine, veterinary medicine, toxicology, forensic science, and research.
- Visual Examination – A method used to examine the eyes of a cat. It is done by having the owner hold the cat’s head still while looking into its eye. The veterinarian then uses a light source to look at the back of the eye. This allows them to see any abnormalities.

Treatment for Feline Eye Infections
There are different types of eye infections in felines. Some require only topical treatment, while others require systemic antibiotics. Depending on the type of infection, treatment can vary. Some medicines are topical, while others are systemic.
Topical treatments are applied directly to the eyes. Topical treatments can be used alone or in combination with other therapies.
- Antibiotics are commonly used to treat bacterial infections. In addition, antibiotic ointment is typically used to treat bacterial conjunctivitis.
- Anti-inflammatories are sometimes used to treat viral infections. Anti-inflammatory drops and eye ointments are available over the counter (OTC).
Systemic treatments are administered orally or intravenously. Systemic treatments are generally reserved for severe cases of eye infections.
- Oral antibiotics are effective against both bacterial and viral infections. Oral antibiotics are only recommended for bacterial infections.
- Intravenous antibiotics are given via injection into a vein. Intravenous antibiotics treat bacterial infections that don’t respond to oral antibiotics.
Other Treatment Options
In addition to the above treatments, other options exist for treating eye infections in felines.
- Homeopathic remedies are natural substances that stimulate the body’s healing mechanisms. Homeopathy is safe and effective for treating minor illnesses such as eye infections.
- Laser therapy uses light energy to destroy pathogens without damaging surrounding tissue. Laser therapy is used to treat bacterial and viral infections.
- Phototherapy involves exposing the skin to ultraviolet radiation. Phototherapy is used to treat fungal infections.
- Steroid injections are injected under the skin to reduce swelling and relieve pain. In addition, steroids are used to treat allergic reactions and inflammatory conditions.
Prevention of Feline Eye Infections
There are several different types of eye infections in cats that can develop. Some of these infections are very common, while others are rarer occurrences. Whether your cat has developed a disease, preventing future problems is always essential.
One of the easiest ways to prevent eye infections is to wash your hands frequently. When washing your hands, clean under your fingernails and between your fingers. Also, avoid touching your eyes or rubbing your eyes. These actions can spread bacteria into your eyes, causing a viral infection in cats.
Preventative measures include keeping your cat indoors, limiting exposure to potential allergens, cleaning his eyes regularly, and treating him with antibiotics if he develops symptoms.
It’s also important to pay attention to your cat’s diet. Make sure that he gets plenty of water and healthy food. Avoid giving him foods that contain raw meat or bones since these items can harbor harmful germs.
Finally, try to limit his exposure to other animals, especially dogs. Dogs can carry diseases that could harm your cat.
Frequently Asked Questions
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