Which condition is given as an example where retinal bleaching can affect pupil responses?

• A. Glaucoma
• B. Cataracts
• C. Rod-cone dystrophy
• D. Dry eye syndrome

Answer: (C)

Pupil responses to light depend on intact photoreceptor signals and the neural pathway from the retina to the brain. Photopigments in rods and cones bleach with light, temporarily changing their sensitivity and how strongly they drive the reflex. In rod-cone dystrophy, photoreceptors are degenerating, so their ability to signal light is already compromised. When bleaching occurs, the reduced photoreceptor function leads to a more noticeable change in the pupil constriction and recovery, making this condition a clear example of how retinal bleaching can affect pupil responses. The other conditions involve different parts of the visual system (optic nerve in glaucoma) or nonretinal factors (media opacity from cataracts, tear-film issues from dry eye), which don’t illustrate the bleaching effect on the retinal-driven pupil reflex as directly.