Stargardt disease (STGD) is an inherited eye condition that gets worse as a dog gets older. This disease affects the parts of the eye that sense light (the photoreceptors), causing them to deteriorate. As the photoreceptors break down, the dog's eyesight becomes worse in both daylight and dim light.
Affected dogs often develop signs of the disease before they are ten years old. These signs can include loss of vision, dilated pupils, and a reduced response to light. Dogs that are affected by Stargardt disease don't usually go completely blind, but retain some degree of vision.