The different tissues of the eye and associated structures can develop primary tumors or can be the site of spreading tumor cells. Tumors of the eye are less frequent in cats than in dogs, but those that occur are more likely to be cancerous (malignant).
Tumors of the Eyelid and Conjunctiva
Eyelid and conjunctival tumors are the most frequent primary eye tumors. These tumors are
Eyeworms (Thelazia californiensis and Thelazia callipaeda) are parasites found in cats, dogs, and other animals, including humans, in the western United States and Asia. They are whitish, 0.25 to 0.75 inches (7 to 19 millimeters) long, and move in a rapid snake-like motion across the eye. Your veterinarian may find up to 100 eyeworms in the conjunctival sac, tear ducts, and the conjunctiva under the ey
Chlamydial conjunctivitis is an infection of the membrane around the eye (the conjunctiva). Different strains of Chlamydia felis and Chlamydia pneumoniae bacteria cause significant eye infections in cats. The disease in cats is also known as feline pneumonitis, which can be misleading because these bacteria rarely cause pneumonia in cats. The infection usually involves the eye and occasionally the nose
Eye disorders can occur because of diseases affecting other parts of the body. They can occur with inherited, infectious, degenerative, and cancerous disorders. Often, discovering a change in the eyes can help uncover the systemic disorder sooner than if the eyes had not been examined. Diseases affecting the blood vessels or nervous system are likely to produce changes in the eyes. If your cat has a disease that affects both eyes, your veterinarian will often look for diseases in
Severe prolapse (slipping out of place) and/or bulging of the eye can be caused by trauma. It is uncommon in cats. The outcome depends on the extent of the trauma, depth of the eye socket, duration of the displacement, resting pupil size, condition of the eye, and other damage near the eye. In cats, forward displacement is usually caused by severe trauma to the head; often, facial bones are broken. The eyeball should be put back in place surgically as soon as possible if th
The optic nerve carries the electrical impulses from the eye to the area in the back of the brain where vision is sensed and interpreted. Injury to the optic nerve usually leads to partial or complete loss of sight.
Optic Neuritis
The most frequent optic nerve disease is optic neuritis, which is inflammation of the optic nerve. When it affects both eyes, signs include dilated pupils that do not respond to
The ocular fundus is the back of the eye opposite the pupil and includes the portion of the white of the eye (sclera) that is in the back of the eye, the retina, the membrane between the retina and the sclera (the choroid), and the optic disk. Diseases of the ocular fundus may occur on their own or as a part of generalized diseases. Inherited abnormalities may be present at birth or appear later, and are important in the cause, develo
The lens is a soft, transparent tissue that sits behind the iris. It helps focus incoming light onto the retina. Common disorders of the lens include those that affect its transparency (such as cataracts), and those that affect the placement of the lens.
Cataracts
A cataract occurs when the lens becomes cloudy or opaque, which effectively blocks light from reaching the retina. Th
Cats, like people, can develop glaucoma. Glaucoma occurs when an imbalance in production and drainage of fluid in the eye (aqueous humor) causes a buildup of fluid that increases eye pressure to unhealthy levels. The increased pressure can cause the destruction of the retina and optic disk (the spot where the optic nerve enters the eye).
Glaucoma occurs less often in cats than in dogs. It usually develops after inflammation of
The uvea (or the uveal tract) is the colored inside lining of the eye consisting of the iris, the ciliary body, and the choroid. The iris is the colored ring around the black pupil. The ciliary body is the set of muscles that contract and relax to allow the lens to focus on objects; it is also the source of aqueous humor, the clear fluid in the eye. The choroid is the inner lining of the eyeball. It extends from the ciliary muscles to the optic nerve at the back of t