Electroretinogram in cone dystrophy.
Electroretinograms (ERGs) in 10 cases of cone dystrophy were studied with special respect to log(bp/bs) that represents the log of photopic ERG amplitude divided by scotopic ERG amplitude. Photopic ERGs were either greatly diminished or nonrecordable, and scotopic ERGs showed either normal or reduced amplitudes. All cases had a low value of log(bp/bs), less than the lower normal limit, indicating significantly greater impairment in cone function than in rod function. These results have proved log(bp/bs) to be helpful in confirming the diagnosis of cone dystrophy especially in cases with recordable photopic ERG and reduced scotopic ERG. Among other ERG parameters, the photopic ERG b-wave implicit time that was determined with averaging and digital amplification of the responses in 4 cases showed prolongation in 3 cases while normal in one case. Oscillatory potentials were nonrecordable or barely recordable in all cases.
Iijima
H
H
Department of Ophthalmology, Yamanashi Medical College, Japan.
Yamaguchi
S
S
Kogure
S
S
Hosaka
O
O
Shibutani
T
T
D000328:Adult; D002648:Child; D003119:Color Perception Tests; D003623:Dark Adaptation; D004596:Electroretinography; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D010786:Photoreceptor Cells; D012162:Retinal Degeneration / Q000235:genetics / Q000503:physiopathology*; D058609:Visual Field Tests; D014794:Visual Fields