The influence of luminance on the multifocal ERG
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To assess the efficacy of high luminance in increasing the amplitude of the multifocal electroretinogram (mfERG). We examined 5 male and 5 female volunteers in the age of 22–52 years (median 28 years). Three different stimulus luminance levels were applied: the bright areas of the stimulus pattern were set to 150, 300 and 500 cd/m2. We recorded the potentials via DTL electrodes using the VERIS Science 4.4 system with 61 hexagons, pupils were dilated. Analysis was based on the 5 ring averages.
Across all hexagons and subjects, the response density (∼amplitude) rose by 20% when increasing the luminance by a factor of 3.3. The peak times decreased slightly with higher luminance, by less then 1.5 ms.
Combining the present results with those from two previous studies, the gain (= relative amplitude increase for relative luminance increase) is close to 0.4 over a range of 56–700 cd/m2. The stimulus luminance range suggested in the mfERG guidelines seems well chosen.
KeywordsAmplitude Luminance mfERG Multifocal ERG Peak time
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We thank our subjects for their ready cooperation and two anonymous reviewers for thorough critique and valuable suggestions.
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