Progressive retinal atrophy (PRA) shows which sequence of photoreceptor loss?

• A. Loss of rods followed by cones
• B. Loss of cones followed by rods
• C. Simultaneous loss of rods and cones
• D. Only cones degenerate

Answer: (A)

Progressive retinal atrophy starts with loss of the rod photoreceptors, which handle vision in dim light. When rods deteriorate first, you typically see night blindness and reduced peripheral vision before daylight vision is affected. As the disease advances, the cone photoreceptors degenerate, leading to diminished central vision and color or color discrimination loss. This sequential pattern—rods first, cones later—is characteristic of PRA. The other scenarios (cones first, simultaneous loss, or only cones) don’t fit the usual progression and clinical signs.