Abnormal dark adaptation kinetics in autosomal dominant sector retinitis pigmentosa due to rod opsin mutation.

Abstract

The time course of dark adaptation was measured in 10 subjects from three families with autosomal dominant sector retinitis pigmentosa (RP) due to mutations in the first exon of the rod opsin gene. In each subject cone adaptation and the early part of the recovery ofrod sensitivity followed the normal time course, but the later phase of rod adaptation was markedly prolonged. The recovery of rod sensitivity is much slower than that reported in any other outer retinal dystrophy. Using a model based upon primate data of rod outer segment length and turnover, we have calculated that the delayed phase of the recovery of rod sensitivity in the RP patients testedfollowingstronglight adaptation could be due in part to formation of new disc membrane with its normal concentration of rhodopsin rather than in situ regeneration of photopigment.

Retinitis pigmentosa: visual function and multidisciplinary management

“…55,86 The loss of rod function is demonstrated by elevated rod dark adaptation thresholds and very slow or non-existent dark adaptation. [87][88][89][90] A representation of these is shown in Figure 1. Retinitis pigmentosa: visual function and management Herse Low luminance perimetry has been suggested as a method to investigate the relative rod dysfunction in RP.…”

The repeatability of the Goldmann-Weekers adaptometer for measuring cone adaptation

“…Abnormal dark adaptation kinetics are diagnostic of a range of conditions, including retinitis pigmentosa [1,2], age-related macular degeneration (AMD) [3][4][5][6], diabetic retinopathy [7,8] and vitamin A deficiency [9,10]. Recently there has been renewed interest in cone dark adaptation because of its ability to identify people with early AMD and the relative speed with which it can be recorded [6].…”

Differential Light-induced Responses in Sectorial Inherited Retinal Degeneration

“…Although protein misfolding or altered trafficking is considered to be the major biochemical features of many RP mutations in Rh (16 -19), some mutations do not induce major structural defects (20,21) but cause changes in G-protein binding and activation (22,23) or the formation of altered photointermediates (24,25), among other phenotypes (17,(25)(26)(27)(28). Sector RP is an atypical form of RP, ranging from stationary to slowly progressive evolution of the retinal degenerative pattern, characterized by regional areas of bone spicule pigmentation, subnormal electroretinogram, and visual-field defects, usually in the inferior quadrant of the retina (29,30).…”