The cornea is the clear dome on the front surface of the eye. It helps to protect the front of the eye and is also important in focusing light on the retina at the back of the eye. Because the cornea is critical for proper vision, it is important to address any disorders or injuries promptly.
Superficial inflammation and swelling of the cornea (superficial keratitis), inflammation and swelling deep within the cornea (interstitial keratitis), and inflammation and swelling of the cornea with slow-healing sores (ulcerative keratitis), can all occur in cats.
Ulcerative keratitis is frequently caused by an infection with feline herpesvirus-1. It can also be caused by foreign objects or defects in the shape or form of the eyelids. This inflammation and swelling of the cornea with slow-healing sores (corneal ulcers) may occur on the surface of the cornea (superficial) or it may affect deeper layers. Secondary bacterial infections are common and can worsen ulcers. Ulcerative keratitis caused by feline herpesvirus-1 can be slow to heal and recur throughout the cat's life. To detect small ulcers, a veterinarian may put drops of a specialized dye into the eye. 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. 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. Your veterinarian can advise you regarding the best treatment for your cat.
Corneal sequestration is a disorder in which part of the cornea darkens and dies. It occurs only in cats. There is a brown to black clouded area in or near the center of the cornea; this is composed of dead connective tissue, blood vessels, and surrounding inflammation. This area (called a sequestrum) can raise up and extrude from the cornea. The condition is painful and causes inflammation in the surrounding cornea. Corneal sequestration occurs in all breeds of cats, but Persians, Himalayans, and Siamese cats are more likely to develop the disorder. Treatment consists of surgery to remove the affected surface of the cornea and, in some cases, covering the defect with grafts of conjunctival tissue.
Also see professional content regarding the cornea.