Detached retina in cats occurs when the innermost layer of tissue in the back of the eye, or retina, detaches from the epithelium and choroid, the outermost layers. Feline retinal detachment usually occurs as a result of fluid build up under the retina. It's often a symptom of a more serious underlying illness.
Causes of Retinal Detachment in Cats
The most common cause of feline retinal detachment is high blood pressure. High blood pressure causes bleeding in the blood vessels beneath the retina. As blood accumulates under the retina, it's pushed away from the other layers of tissue at the back of the eye. Hyperthyroidism and chronic kidney disease are common causes of high blood pressure in cats.
Hyperviscosity syndrome is another cause of detached retina in cats. In hyperviscosity syndrome, too much protein accumulates in the blood and the blood becomes too thick. This can cause the small blood vessels at the back of the eye to rupture, leading to bleeding inside the eye and the accumulation of fluids beneath the retina. Other blood problems, including overproduction of red or white blood cells or blood clotting disorders, can cause hemorrhaging of the eye and lead to retinal detachment.
Additional causes of feline retinal detachment include infection by bacteria, fungus or parasites. Degenerative diseases of the eye can play a role, as can cancerous tumors, injury and exposure to toxins.
Symptoms of Feline Retinal Detachment
Blindness or vision loss is the most obvious symptom of detached retina in cats. The more the retina separates from the tissues of the inner eye below it, the more vision loss can occur. If your cat's retina becomes completely detached from the inside of his eye, he could lose sight in that eye altogether.
Other symptoms of detached retina in cats include dilated pupils. Your cat's pupil will slowly lose its ability to react reflexively to light as your cat's retina becomes further separated from the tissues of the inner eye. As your cat's retina becomes more detached, his pupil will dilate more slowly. When your cat loses sight altogether, the pupil will cease to dilate at all.
Your cat's eye may change in appearance, especially if blood has accumulated in the eye or if the eye is inflamed.
Diagnosing Retinal Detachment in Cats
Your vet will need a complete medical history and physical exam to determine the extent of your cat's retinal detachment. A veterinary eye exam will be in order, and your cat may need to see a veterinary ophthalmologist. A range of tests, including blood tests, hormone level tests, fecal exams, urinalysis, X-rays and ultrasounds may be used to determine the underlying cause of your cat's detached retina.
Treatment will depend upon the cause of your cat's retinal detachment. Medications can lower blood pressure to treat most cases of feline retinal detachment. Surgery may be needed to repair the damage. Some cases of detached retina in cats can't be treated.