Which clinical sign is indicative of progressive retinal atrophy?

The indication of progressive retinal atrophy (PRA) is indeed the narrowing and loss of retinal blood vessels. This condition is characterized by a gradual degeneration of the photoreceptors in the retina, particularly the rods and cones, leading to a progressive decline in vision. As the photoreceptors deteriorate, the retinal pigment epithelium (RPE) and other supporting structures may also be affected.

Over time, this degeneration is reflected in specific changes that can be observed during an ophthalmic examination. One of the hallmark signs is the narrowing and eventual loss of retinal blood vessels as the supporting tissues become compromised. This finding suggests a chronic process of degeneration rather than an acute event, which aligns with the slow and progressive nature of PRA.

In contrast, acute photoreceptor death is not characteristic of PRA; this condition leads to gradual loss rather than sudden changes. A normal fundus appearance would generally indicate the absence of significant retinal changes associated with PRA, and sudden bilateral vision loss would suggest other conditions or acute events, rather than the insidious progression typical of PRA. Thus, the presence of narrowed and lost retinal blood vessels is an important diagnostic indicator of this disease.