Common Causes of Corneal Disease in Cats

What is the cornea?

The eye surface, or cornea, is a very clever structure. It’s a specific form of skin that covers the eye and protects the internal contents. The cornea is transparent, allowing light to pass through and be processed in the deeper layers of the eye.

1. Feline Herpes Virus Infection (FHV-1)

FHV-1 can cause signs of cat flu such as sneezing, fever, and lethargy. Additionally, it has a particular ability to infect the eye. This not only infects the superficial conjunctiva (causing conjunctivitis), it can also infect the surface of the eye.

FHV-1 can cause cloudiness, pain and an eye ulcer (see below). Herpes virus is often suspected due to the clinical signs and appearance of the eye ulcer but can also be detected on a swab. It can be treated with anti-viral medication; however, the course is long and expensive.

Unfortunately, the ulcer can appear healed while lingering for months to years before reappearing. FHV-1 often reappears during times of stress so it’s important to keep known stressors to a minimum in affected kitties. FHV strains are included in the flu vaccine (FVRCP) and can help protect kittens from an initial infection. The vaccine is unlikely to help cats with active infections.

2. Eye Ulcers

Any damage to the cornea causing a loss of integrity of the surface is called an eye ulcer. These can be superficial, affecting just the upper layers of the cornea, or deep. Eye ulcers can be caused by trauma such as a scratch. This occurs commonly in cats after fighting with another cat.

Other causes of eye ulcers include foreign material such as small thorns or foxtails that become lodged on or near the cornea. As previously mentioned, feline herpes virus is also known to cause eye ulcers in cats.

An ulcer is in danger of becoming infected and enlarging, particularly if it’s deep or caused by a contaminated cat claw. The cornea can repair itself effectively, but most ulcers require treatment with antibiotic eye drops and pain medication. They can worsen quickly if they become infected and all require prompt veterinary attention. Occasionally, if the ulcer is large and deep, surgery will be required.

3. Keratitis and Sequestrum

Keratitis simply means inflammation or infection of the cornea. There’s normally an underlying cause of the keratitis. These include an immune reaction called eosinophilic keratitis, reduced tear production (less common in cats vs dogs), rubbing of hairs on the eye, or an inability to blink properly. The latter is usually seen in short-nosed breeds with large eyes such as Persian cats.

These breeds are also prone to a condition called corneal sequestrum. A sequestra is a dark spot that develops and enlarges on the cornea. It must be cut out surgically and can be challenging to treat.

Other Diseases of the Cornea

Less commonly, the cornea can become infected with fungus or yeasts. These may look like an eye ulcer but fail to heal.

Each of these conditions is serious and can cause vision impairment or blindness in cats. Therefore, seeking veterinary attention as soon as possible is very important.

Read more:

A Vet’s Advice: Eye Exams and Eye Care for Your Pets

Giving Your Pet Eye Medication: Step-by-Step Instructions

Blindness in Cats and Dogs

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