Feigl B.

Department of Ophthalmology, Karl Franzens-University of Graz, Austria

Background: In the RETIscan multifocal ERG version 3.1 61 hexagons are presented according to a pseudorandom binary m-sequence (60 frames, luminance 180 cd/m2, contrast 99%). The number of the segments can be chosen between 1-8 (each lasting 43 seconds). For analysis amplitudes for each location or group averages in concentric rings for ampliutdes as well as for latencies can be used. The purpose was to find the best reproducable protocol.
Patients and methods: 17 normal subjects (age 25-35, mean 28) were tested monocularily with DTL- electrodes and dilated pupils on two different days. The protocols consisted of 2, 4 and 8 segments which followed each other in 2 minutes steps. For analyses concentric ring averaging for amplitudes and latencies were used.
Results: Within the subjects amplitudes and latencies showed greatest varibility in the 2 segment protocol (for amplitudes almost two times higher in comparison to the 8 segment protocol) and the 4-segment protocol.There was no predeliction of a special ring for amplitudes but latencies showed a higher variability for ring 1which was lesser throughout ring 2-5. Greatest interindividuell variability was found in the 1. ring and to a lesser extend in the more peripherial areas . This was shown more for the amplitudes.
Discussion: We suggest using the 8-segment protocol for clinical use In diseases mainly concerning latencies also shorter protocols can be helpful.

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