At the beginning of retinitis pigmentosa, which vision is primarily affected?

Retinitis pigmentosa is a genetic disorder that primarily affects the photoreceptor cells in the retina, specifically the rods and cones. At the onset of this condition, the rods—which are responsible for peripheral and night vision—are typically the first to be affected. This leads to the characteristic symptoms of narrowing visual fields and difficulties in low-light conditions, significantly impacting peripheral vision.

As the disease progresses, individuals may also experience difficulties with color vision and eventually central vision, but these issues generally occur later in the disease course. Initially, patients often maintain good central vision while losing the ability to see peripherally, making peripheral vision the primary area of concern at the beginning of retinitis pigmentosa. This progressive loss of peripheral vision can eventually lead to "tunnel vision," where only a small central part of the visual field remains intact.