THE SCOTOPIC ELECTRORETINOGRAM TO BLUE FLASHES AND PATTERN-REVERSAL VISUAL-EVOKED POTENTIALS IN INSULIN-DEPENDENT DIABETES

Pattern reversal visual evoked responses (PR-VEPs), the electroretinog ram (ERG) to blue flashes of light in dark adaptation, the steady stat e ERG to 40 Hz flicker, and alterations in pupil diameter following da rk adaptation were studied in 56 juvenile onset diabetics, 34 of whom had no ophthalmoscopic or photographic evidence of diabetic retinopath y (DR group). The remaining 22 had mild background retinopathy (DR + g roup). Normal data was obtained from 24 subjects matched for age and s ex with diabetics. Skin electrodes were used for all recordings. The s cotopic 'b' wave of the ERG was significantly lower in amplitude in th e DR- diabetics and it was even more reduced in the DR + group. The PR -VEP was significantly delayed in diabetics but there was no differenc e between the two groups. The steady state ERG was not significantly d ifferent between normals and diabetics. These findings indicate that r etinal and more central abnormalities develop early in diabetics. Dete ction of objective electrophysiological abnormalities may be used to i dentify persons al risk of developing retinopathy and to monitor the e ffects of treatment.