The scotopic threshold response in diabetic retinopathy--a preliminary report

The scotopic threshold response (STR) and the scotopic b-wave of the electroretinogram were recorded in a group of 30 patients with insulin-dependent diabetes mellitus. Retinopathy was assessed using colour stereo fundus photography and an adaptation of the Airlie House classification scheme. Wide-angle fundus fluorescein angiography was also performed and angiograms were graded for the presence of leakage and capillary non-perfusion. The STR was reduced in those eyes with retinopathy of grade 3 or above compared with eyes with retinopathy of grade 2 or below. There was a significant correlation between the amplitude of the STR and: (1) the grade of retinopathy; and (2) fluorescein leakage. There was no correlation between the b-wave amplitude and the severity of retinopathy. The STR may have a role as a screening test for diabetic retinopathy.