Introduction
The signs of progressive retinal atrophy (PRA) can appear early or later in life and can be slow or sudden in onset. The dog’s familiarity with its environment often delays diagnosis, because its vision impairment can be quite difficult to detect.
Symptoms of Progressive Retinal Atrophy in Dogs
Usually, the first sign of progressive retinal atrophy is night blindness, including a reluctance to go outside at night or to navigate unfamiliar areas in dimness or darkness. Other signs can include:
- Reluctance to jump on or off furniture during darkness
- Night blindness (nyctalopia); reduced vision in dim light
- Sluggish pupilary light responses
- Decreased menace response
- Cloudy or opaque eye surface; grayish discoloration of the surface of the eye
- Greenish sheen to the eye
- Cataracts
- Bumping into furniture or walls
- Tripping or stumbling over objects
- Pawing at the air when going down stairs
- Reluctance to navigate stairs
Dogs At Increased Risk
Early-onset, slowly progressive PRA causes night blindness during the first year of life, although affected dogs may retain daytime vision for a year or more. Affected breeds include the Akita, Tibetan Terrier, Dachshund, Gordon Setter, Miniature Schnauzer and Norwegian Elkhound, among others.
Early-onset, rapidly progressive PRA causes vision impairment that starts in the first year of life and progresses to blindness within a matter of months. Breeds affected by this form of PRA include the Irish Setter, Cardigan Welsh Corgi and Collie, among others.
PRA can also occur after 2 years of age, with complete blindness usually occurring by age 4. Dogs affected by this form of the disorder include the Border Collie, Afghan Hound, Miniature and Toy Poodle, Cocker Spaniel, Tibetan Terrier, Akita, Samoyed, Siberian Husky and Labrador Retriever, among others.
Healthy, middle-aged and older female dogs between 6 and 14 years of age tend to develop a sudden and severe form of progressive retinal atrophy, where vision is completely lost in both eyes over the course of several hours to several days. Males are less commonly affected by this form of the disease.