On- and off-repone of the photopic electroretinogram in x-linked juvenile retinochii

PURPOE: To examine the phyiologic condition of the middle retinal layer of patient with X-linked juvenile retinochii (xlR) by tudying the on- and off-repone of the photopic electroretinogram (ERG). METHOD: Eleven unrelated Japanee men (mean age; 24.9 ± 7.6 year) who were clinically diagnoed with xlR and molecularly confirmed a having XLR1 mutation were invetigated. For the photopic ERG, the a-, b- and d-wave amplitude elicited by long duration timuli were recorded, and the repone from the xlR patient were compared to thoe recorded from normal ubject (n = 14, mean age, 27.5 ± 4.5 year). We alo examined the relationhip between the photopic ERG repone and the genotype. REULT: No ignificant difference wa found between the a- and d-wave amplitude in the xlR patient (34.2 ± 8.7 μV, 52.5 ± 10.4 μV, repectively), and thoe in normal ubject (40.4 ± 10.3 μV, 44.7 ± 6.3 μV, repectively). The mean b-wave amplitude in the xlR patient wa ignificantly maller (10.5 ± 7.7 μV) than the mean of normal ubject (46.4 ± 10.2 μV) (P < 0.0001). No ignificant correlation wa found between the ERG repone and the locu of the mutation. CONCLUION: The photopic ERG demontrated coniderable impairment of the on-pathway ariing from an abnormality of the on-bipolar cell or poibly econdary to Müller cell abnormality in xlR