Scotopic threshold response in complete and incomplete types of congenital stationary night blindness.
OBJECTIVE
To study the function of the rod visual pathway in the complete and incomplete types of congenital stationary night blindness (CSNB), with special reference to the scotopic threshold response (STR) of electroretinograms (ERGs)


METHODS
Using full-field stimuli with light intensities ranging from near absolute threshold to bright, ERG intensity series from two patients with complete CSNB, four patients with incomplete CSNB, and four normal subjects were recorded.


RESULTS
Neither the rod b-wave nor the STR was recordable from the patients with complete CSNB. In the patients with incomplete CSNB, the STR was clearly recorded, although the absolute threshold was elevated in accordance with elevation of the psychophysical absolute threshold. The b-wave stimulus threshold was not elevated, and the b-wave amplitude near the threshold was normal. The peak time of the STR was delayed by approximately 80 msec, whereas that of the b-wave was normal.


CONCLUSIONS
These STR results indicate that the rod system abnormality in complete CSNB differs from that in incomplete CSNB. Furthermore, the greatly delayed peak time of STR in the patients with incomplete CSNB made the interaction between b-wave and STR different from that in normal subjects.
Miyake
Y
Y
Department of Ophthalmology, Nagoya University School of Medicine, Japan.
Horiguchi
M
M
Terasaki
H
H
Kondo
M
M
D000293:Adolescent; D000328:Adult; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009755:Night Blindness / Q000151:congenital* / Q000503:physiopathology*; D010775:Photic Stimulation; D011601:Psychophysics; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D012684:Sensory Thresholds; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception