Early retinal degeneration (ERD) is an inherited eye disease affecting dogs. ERD usually presents at 3 to 10 weeks of age as general poor vision and night blindness. Affected puppies may appear to move more cautiously than littermates and have a tendency to bump into objects. ERD occurs as a result of abnormal development and degeneration of Photoreceptor Cells (Rod and Cone Cells) of the Retina, which are responsible for sensing light and transmitting signals to the brain, resulting in vision. The disease initially progresses rapidly, but progression slows after 6 months of age. Dogs become totally blind between 12 to 18 months of age. Between 4-5 years of age, affected dogs also develop cataracts.