[Photostimulation that induces flattening of photopic electroretinograms--first report. An apparatus for slope photostimulation].
OBJECTIVE
We developed a new photostimulation system for electroretinograms (ERGs). This apparatus is capable of varying the transients during stimulus on and off (up-slope and down-slope times, respectively) as well as the stimulus and background intensities. We applied this system to evaluate the photopic ERG in human eyes.


METHODS
Seven normal volunteers and a 43-year-old patient with pre-proliferative diabetic retinopathy served as test subjects. We recorded ERGs with relatively long intervals of up-slope and down-slope times for photostimulation.


RESULTS
As the up-slope and down-slope times were increased, the amplitude was reduced and the peak latency was prolonged for both the on and off responses. When the normal subjects' retinas were stimulated with a 341-msec up-slope time and a 34.1-msec down-slope time, the ERG waves showed complete flattening in both on and off responses. The ERGs of a patient with pre-proliferative diabetic retinopathy showed much longer peak latency than that of the normal volunteers as the up-slope time was prolonged. When the patient's retina was stimulated for a prolonged up-slope time, the average of the amplitude of ERG waves was similar to that of the normal volunteers.


CONCLUSIONS
These results suggest that this new type of photostimulation might potentially uncover some novel aspect of clinical ERGs and might be useful for testing retinal functions of patients with diabetic retinopathy.
Uno
N
N
Department of Ophthalmology, Kinki University School of Medicine, Japan.
Tahara
K
K
Nakao
Y
Y
Otori
T
T
D000328:Adult; D003930:Diabetic Retinopathy / Q000503:physiopathology; D004596:Electroretinography; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000295:instrumentation*