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L. Alswede, B. Jurklies; The Effects of Media Opacities on the Multifocal Electroretinogram . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3432.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the influence of media opacities such as cataract on the multifocal electroretinogram (mfERG) responses. Methods: Multifocal electroretinograms were obtained from 24 patients with mild to moderate cataract. Each patient underwent mfERG recordings (VERIS, EDI, San Francisco, USA) prior to and and seven days following cataract surgery. A stimulus array of 103 hexagons, a maximum stimulus intensity of 300 cd/m² with a contrast of 99% were used to measure electric signals within a central retinal area of approximately 50° in diameter. Six concentric ring groups were formed and latencies and response density amplitudes of N1 and P1 of the first order kernel responses were analyzed. For statistical analysis, the Wilcoxon Rank Sum Test for connected samples was applied. Results: Significant differences in comparision between preoperative and postoperative responses were found for response density amplitudes of the N1 and the P1 component, but not for implicit time of those two waves. Amplitudes of all six ring groups were significantly larger after phacoemulsification of the cataract and implantation of a clear artificial intraocular lens. Postoperative amplitudes of P1 showed a mean increase of 25.8% overall, in a range from 24.0% in most peripheral ring6 to 27.4% in central ring1. There were no significant implicit time differences evident in mfERG recordings following cataract surgery for none of the chosen eccentricities. Conclusions: Media opacities like cataract may have a significant impact on mfERG recordings. Therefore media opacities should be considered as a cause of an isolated decrease in response density amplitudes and traces. In contrast, implicit times were not affected in a statistically significant manner. Therefore, changes in implicit time of the mfERG in the elder population may be related more to alterations in retinal neurotransmission than to media opacities. The clinical assessment of both the media opacities and the retinal status should be considered in interpretation of the mfERG recordings.
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