[The influence of experimental scotoma on multifocal electroretinogram].

ABSTRACT

PURPOSE: To detect the sensitivity and the repeatability of multifocal electroretinogram (mfERG). METHOD: The effects of experimental absolute and relative scotomas on mfERG with 103 hexagons were observed on 8 normal eyes. The scotomas were produced by simultaneous and multi located masks on the hexagons of the screen in 6 different locations with black paper, and the neutral filters of 0.3 and 0.6 log unit. The repeatability was evaluated by analysis the data from 5 unmasked hexagons in 4 successive tests. RESULTS: When the hexagons were 1/2 or wholly masked with the black paper and the two kinds of the filters, the amplitudes of N1 and P1 waves in these areas were significantly decreased as with the reduced transferability of light. When the hexagon was 1/3 masked, there were no significant differences between the different kinds of mask and the unmasked control. There were no significant changes in the datas from the selected unmasked hexagons in the 4 successive recordings. CONCLUSION: mfERG is an unique sensitive visual electrophysiological test with high sensitivity and good repeatability. When 103 hexagons stimulating pattern is used, it could detect the scotoma larger than 1/3 of each hexagon.