Vision threshold profiles in X-linked retinitis pigmentosa.

Absolute thresholds for blue-green and red stimuli were measured along the horizontal and vertical meridans in two patients with X-linked retinitis pigmentosa. From these data, we deduced that cones mediate detection of both stimuli in the central 10 degrees, there is a ring scotoma in the mid-periphery, and in the far periphery rods mediate detection of both stimuli. Conclusions drawn from the psychophysical measures about rod and cone function across the retina are in point-by-point agreement with the data of a recent electron microscopic study by Szamier et al. on the retina of a 24-year-old X-linked retinitis pigmentosa patient.