Yonago Acta medica 1993;36:112-122

Monochromatic Flash Early Receptor Potential and its Clinical Application

Akihiko Tamai, Hiroshi Nakao, Norio Miki, Nanae Kunito, Hiromi Matsui, Yoshika Takahashi, Shigeru Takagi, Hiroyuki Sugimori, Masao Nagata and Atsushi Yamasaki

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

The human early receptor potential (ERP) was studied by monochromatic flashes in 16 dichromats (6 protanopes, 12 eyes, and 10 deuteranopes, 20 eyes), 7 patients (14 eyes) with autosomal dominant cone dystrophy and 28 diabetics (55 eyes) with or without diabetic retinopathy. The color filters used were MIF interference filters No. 21, No. 14 and No. 7 for the red, green and blue flash ERPs, respectively. The ERP amplitude was measured between the peaks of the initial cornea-positive phase (R1) and the later cornea-negative phase (R2). The mean ratio of the blue flash ERP amplitude to the red flash ERP amplitude was clearly different among normal individuals, protanopes and deuteranopes, indicating a new, useful index for the objective clinical detection of congenital red-green color defects. The mean amplitudes of the ERP to red, green and blue flashes were much reduced in the patients with cone dystrophy compared with normal controls. As a result, not only does the monochromatic flash ERP disclose that a primary site of the affected lesion is present in the cone cells in this entity with an autosomal dominant inheritance, but also that the ERP is of great clinical value in detecting functional deterioration of the cones at the level of the receptor outer segments. In diabetics, significantly decreased ERP amplitudes to the respective flashes were detected from the initial stages of diabetic retinopathy and beyond, suggesting that the ERP recording is of high clinical value in the early diagnosis of diabetic retinopathy or maculopathy and in detecting its grade and prognosis.

Key words: cone dystrophy; deuteranopes; diabetic retinopathy; monochromatic flash early receptor potential; protanopes; visual pigments

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