Progressive Retinal Atrophy in Cats

Progressive retinal atrophy, commonly called PRA, is a disease that causes gradual degradation and death of cells in the eye. PRA is relatively rare in cats, but purebred cats are far more likely than common housecats to suffer from PRA. The incidence is highest in Abyssinians, though some cases have been reported in the Persian and Siamese breeds.

  1. Diagnosis

    • Other illnesses or injury can cause similar symptoms.

      Diagnosing PRA involves ruling out other potential causes of vision loss, such as head or eye injury, infection with feline immunodeficiency or feline leukemia virus, or prenatal infection with toxoplasmosis parasite. Retinal degeneration can also be caused by taurine, vitamin A, or vitamin E deficiency, and is common in cats that are fed homemade diets.

    Progression

    • It may take quite some time to notice signs of PRA.

      The effects are gradual but painless and begin shortly after the kitten opens its eyes, when the cells of the retina first develop. After a brief period of normal vision, the cat's ability to sense light slowly declines. Vision initially becomes poor at night. As cells continue to die, vision in daylight is lost as well, terminating in complete blindness by age 5. Owners often fail to notice early signs because cats naturally adapt to relying on smell, hearing, and memory rather than vision.

    Causes

    • The feline PRA gene is rare.

      Feline PRA is a genetic disease. It is found in purebred animals because they have been inbred over generations to increase desirable traits. Unfortunately, this increases harmful traits as well. The gene for PRA is both rare and recessive, which means that its effects are blocked by a dominant, healthy gene in most cats. In cats with PRA, the defective gene has no competing gene to prevent its effects.

    Nutrition

    • Commercial diets are nutritionally sound.

      There is no known method of preventing PRA in an affected cat. However, some nutrients support eye health. A balanced diet with appropriate amounts of taurine, vitamin A, and vitamin E may slow degeneration. High-quality, commercial diets have correct amounts of these nutrients. Pet fad diets and frozen food are notorious for causing deficiencies. Consult a qualified animal nutritionist before giving supplements.

    Breeding

    • Affected cats always have an affected parent or grandparent.

      PRA continues to be inherited because cats who carry the disease continue to be bred. If your cat shows symptoms, do not breed it. All affected cats should be spayed or neutered. If you purchase an affected purebred, report the case to the breeder, who may not have noticed disease progression in the parent animal. If you intend to purchase a purebred, seek out information on the parent lines before choosing an animal. Shelters have many healthy cats of all breeds and all ages.

    Coping with Blindness

    • Blindness will not prevent high quality of life for your cat.

      Blindness in a cat is not a disaster. If the cat is kept in familiar, safe surroundings, its quality of life will not be greatly affected. Keep the cat indoors and away from dangerous areas like hot stoves and open water. Make sure your home is calm and that rowdy animals and children do not frighten or chase the cat. Keep your pet's environment neat and consistent, and it will get around just fine. Remember, these cats adapt so well that it takes most owners months or years to notice their progressive blindness.