Progressive retinal atrophy (PRA) is a hereditary condition that results in vision loss in dogs (as well as humans). Blindness has many causes and can be a common health issue in dogs, especially if they’re older. It may sound scary, but dogs are able to cope well with blindness thanks to their other senses. PRA specifically is a non-painful loss of vision that occurs over a period of time. Loss of vision can take 1 to 2 years to be complete.
What causes blindness in progressive retinal atrophy?
The retina perceives images through photoreceptors that collect information about light. There are two types of photoreceptors in the retina: rods and cones.
Rods gather information about light intensity and are used more for night vision. Cones distinguish between colors and are more helpful for day vision. In most forms of PRA, the rods degenerate first so a dog’s night vision will wane before its day vision.
Embark tests for over a dozen different mutations that are known to cause PRA in one or more breeds. Most of these variants are recessive, meaning a dog must inherit a copy of the variant from both parents to be at risk for PRA. Some mutations, like the one found in English Mastiffs and Bullmastiffs, are dominant, however. Only one copy of a dominant variant is needed to put a dog at risk of developing the disease.
How to tell if your dog has PRA
A comprehensive ophthalmologic examination by a veterinarian is the only way to diagnose progressive retinal…