[Assessment of foveal function in eyes of patients with exudative age-related macular degeneration before and after argon laser treatment]

Abstract

Purpose: 1. Can foveal cone electroretinogram (FCERG) be a useful diagnostic test in evaluation of efficacy of argon laser treatment in eyes with exudative (wet) age-related macular degeneration (AMD)? 2. Comparison of FCERG with visual acuity, static perimetry and fluorescein angiography results.

Material and methods: FCERGs were recorded from 30 eyes with mean visual acuity 0.6 (Snellen Table) of 20 patients (mean age: 61 years) with wet AMD. The fovea was stimulated with 5-degree flickering light spot (f = 31.25 Hz), surrounded by a 20-degree annulus of intensive steady retinali illuminance. FCERGs were recorded and analysed in amplitude according to the computer-aided method recently put in practice in our laboratory. FCERGs were obtained twice for each AMD patients: before and 3 months after argon laser treatment. Electrophysiological data were also compared with the results of fluorescein angiography, visual acuity and static perimetry.

Results: In the group of patients with wet AMD, significant increase of FCERG amplitude (p < 0.001) after laser treatment was obtained in group I (33% of analysed eyes) and there were mainly patients with extrafoveal choroidal neovascularisation (CNV). Significant decrease of FCERG amplitude (p < 0.01) was obtained in group II (67% of analysed eyes). These were mainly patients with subfoveal CNV and also with extrafoveal CNV. In both groups after laser treatment we did not receive significant changes in visual acuity and macular perimetric mean sensitivity.

Conclusions: These findings suggest that foveal cone ERG can be a useful, independent from fluorescein angiography, test for objective evaluation of efficacy of argon laser treatment in patients with wet AMD, opposite to visual acuity and static perimetry (macula threshold) examinations. FCERG probably indicates patients with better or worse prognosis.