Bültmann S.; Rohrschneider K.

Universitäty Eye Clinic Heidelberg, INF 400, D-69120 Heidelberg

Purpose: The new technique of multifocal electroretinography (MERG) using the SLO allows electrophysiological examination under simultaneous visualization of the fundus. Prior to application in a clinical routine setting it is important to determine the reproducibility of this technique as well as the adequate stimulation intensities during use of monochromatic light.
Methods: 30 eyes of 30 normal probands (visual acuity =1,0) were examined using the SLO (Rodenstock, Germany) for MERG (dilated pupils, gold-foil electrodes) Two test patterns (7 and 19 hexagons) in a 20 degree field were applied. MERG was performed using the RETIscan (Roland Consult, Germany) for stimulation and evaluation. Three measurements were performed for each type of sequence. Stimulus intensity varied between 72 and 300 cd/m2 on minimal background illumination.
Results: While only the 7-hexagon testpattern showed sensible results but without any reproducibility at 72 cd/m2, all test patterns presented a clear ERG signal at 235 cd/m2. This stimulus intensity was tolerated by all probands during the testing-period. There was a wide range in the P1 amplitudes, but good reproducibility could be found intraindividually for both types of sequences. The coefficients of variation for the center, ring 2 and ring 3 of the ring analysis were: 19-Hex:13,6/9,0/8,4% und 12,1/9,6% 7- Hex.
Conclusions: There is good intraindividual reproducibility of P1 for the RETIscan system with the SLO with a wide variation of interindividual values. Good reproducibility for low stimulus intensities on dark background might be due to little straylight and bleaching. In ring analysis of smaller hexagons, the central hexagon is more vulnerable to instability of fixation than the surrounding rings. Supported by DFG grant Ro 973/11-1

Copyright © Deutsche Ophthalmologische Gesellschaft, 2001. All rights reserved.

Last updated: 

Webdesign: SPALLEK.COM