Steady-state pattern electroretinogram in insulin-dependent diabetics with no or minimal retinopathy

Steady-state pattern electroretinogram (PERG) in response to sinusoidal gratings (1.7 c/deg spatial frequency; 9 x 9 deg field size) temporally modulated (sinusoidally) at 8 Hz were recorded in 40 insulin-dependent diabetics and 28 age-matched normal subjects. Visual acuity was greater than or equal to 20/20 in all 40 patients; 31 (62 eyes) showed no sign of retinopathy and nine (18 eyes) showed a few microaneurysms on fluorescein angiography. Insulin-dependent diabetics showed a significant reduction in the PERG mean amplitude as compared with age-matched control subjects (one-way analysis of variance: p less than 0.0001). Significant differences were observed between normals and diabetics without retinopathy (Scheffé test: p less than 0.0001), normals and diabetics with early retinopathy (Scheffé test: p less than 0.0001), no retinopathy and early retinopathy patients (Scheffé test: p less than 0.05). In diabetics without retinopathy multifactorial analysis of variance revealed a significant effect of age of onset of the disease (p less than 0.01) and an interaction effect between age of onset and duration (p less than 0.001) on PERG amplitude. These results suggest a possible use of the steady-state PERG to detect early macular dysfunction in insulin-dependent diabetics.