EARLY MACULAR DYSFUNCTION DETECTED BY FOCAL ELECTRORETINOGRAPHIC RECORDING IN NON-INSULIN-DEPENDENT DIABETICS WITHOUT RETINOPATHY

The focal electroretinogram, which measures the functional integrity o f the distal retina of the the macula, was recorded with a hand-held s timulator-ophthalmoscope in 26 eyes from patients with non-insulin-dep endent diabetes mellitus with normal fundus photography, and in 52 con trol eyes of similar age range. Implicit time and amplitude of the res ponses were studied as a function of the age, glycemic control through glycosylated hemoglobin measurement and duration of diabetes. Implici t time and amplitude were significantly delayed (F=5.05, p=0.028) and reduced (F=11.26, p=0.013) in diabetic patients without diabetic retin opathy compared to control subjects. Moreover, there was a significant relationship between the implicit time (r=0.57, p=0.002) and amplitud e (r=-0.65, p=0.0004) with the duration of diabetes but not with hemog lobin Ale. These results strongly suggest an early macular dysfunction in noninsulin-dependent diabetes mellitus before the appearance of di abetic retinopathy.