Assessment of the Pattern-Reversal Electroretinogram in Diabetes Mellitus

Nanae Kunito, Junji Ha]namoto, Shigeru Takagi, Norio Miki, Kazuki Matsuura, Kimiko Kawai, Yuji Sasaki, Mika lshihara, Masao Nagata and Akilriko Tamai

Department of Ophthalmology, Faculty of Medicine, Tottori University, Yonago 683, Japan

The assessment of transient (2 Hz) pattern-reversal electroretinogram (pattern ERG) was designed in 79 type II, non-insulin-dependent diabetics (158 eyes). Of the diabetics, 46 eyes were with no detectable diabetic retinopathy (DR) (stage 0 of Fukuda's DR classification); 44 eyes with benign DR (slight background stage A I, 20 eyes; severe background A II, 24 eyes) and 68 eyes with malignant DR (preproliferative stage B I, 44 eyes; early proliferative stage B II, 24 eyes). Mean latency of the P₁ (an initial positive deflec-tion of the pattern ERG) showed significant prolongation in the stages A I to B II (P < 0.05 to 0.0001) and in the stage B H (P < 0.001), compared with the respective data of 150 eyes of 75 normal subjects and 46 eyes with no DR (stage 0) of 23 diabetics. The mean amplitude of the P₁ significantly decreased in the stages A II to B II (P < 0.05 to 0.001) and in the stages B I and B II (P < 0.01 and P < 0.0001), compared with the respective data of the above-described normal and diabetic subjects' eyes. No significant prolon-gation in the mean P₁ latency was observed, but a significant reduction in the mean P₁ amplitude (P < 0.001) was detected in the diabetic group with malignant DR (stages B I and B II), compared with the diabetic group with benign DR (stages A I and A II). It thus appears that the P_l component of the pattern ERG, especially its amplitude, is an effective and useful parameter for the early detection of proliferative DR.

Key words: amplitude; diabetic retinopathy; pattern-reversal electroretinogram; P₁component; type II diabetics

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