Rod and cone a-wave in three cae of bietti crytalline chorioretinal dytrophy

PURPOE: To etimate retinal function in Bietti crytalline chorioretinal dytrophy uing the electroretinogram. METHOD: In thi obervational cae erie, the cotopic and photopic electroretinogram in three Japanee female patient (cae 1, 55 year old; cae 2, 56 year old; cae 3, 47 year old) who howed bilateral crytalline retinal depoit but no corneal depoit were recorded. The rod and cone a-wave were analyzed by uing the method decribed by Hood and Birch (1995, 1997). The parameter Rmp3 (maximum a-wave amplitude) and (enitivity) were calculated. REULT: In cae 1, the rod Rmp3 wa decreaed in both eye. The rod in the right eye wa within the normal range, but that in the left eye wa ignificantly reduced. Although the cone Rmp3 wa decreaed, the cone wa within the normal range. In cae 2, the rod and cone Rmp3 wa reduced, but the rod and cone wa within the normal range in both eye. In cae 3, the rod and cone Rmp3 and were within the normal range. CONCLUION: Electroretinogram illutrated different dieae tage, however, no eye with normal Rmp3 and decreaed wa found in rod and cone. In the early tage of thi dieae, decreaed number of photoreceptor and/or outer egment hortening may be preent while phototranduction remain normal. A the damage to the retina progree, phototranduction become everely affected. Becaue reduced cone wa not oberved in our cae, cone may be le involved than rod in thi dieae