On- and off-responses in the photopic electroretinogram in complete-type congenital stationary night blindness.
We examined the on- and off-responses of the photopic electroretinogram in patients with complete congenital stationary night blindness. Standard flash electroretinograms as well as those produced in a ganzfeld modified for long-duration light stimuli (500 msec) permitted the separation of on- and off-responses in four patients and four normal subjects. The amplitude and latency of the elctroretinogram on-response (a- and b-waves) and off-response (d-wave) in addition to the oscillatory potentials of the off-response in normal subjects and patients were compared. The abnormal on-response was demonstrated in all the patients, and the off-response with its oscillatory potentials were preserved. We showed that the second portion of the off-response (of inner retinal origin) is normal. If congenital stationary night blindness is a defect of depolarizing bipolar cells, these results preclude input of the depolarizing bipolar cells and support the hyperpolarizing bipolar cells as the cellular origin of the off-response electroretinogram.
Quigley
M
M
Department of Ophthalmology, Hôpital Sainte-Justine, Montreal, Quebec, Canada.
Roy
M S
MS
Barsoum-Homsy
M
M
Chevrette
L
L
Jacob
J L
JL
Milot
J
J
D000293:Adolescent; D000328:Adult; D002648:Child; D003623:Dark Adaptation; D004596:Electroretinography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009755:Night Blindness / Q000151:congenital* / Q000503:physiopathology*; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000503:physiopathology*