Aging-related changes in the multifocal electroretinogram.

The multifocal electroretinogram (MERG) was recorded in the central 36 degrees-diameter field in 26 young (19-30 yr) and 20 old (60-74 yr) adults in normal retinal health according to a fundus grading scale. The mean amplitude densities of the first-order and second-order responses in this retinal region were lower for old adults compared with young. The aging-related reduction of the first-order amplitude density was greatest at the fovea and decreased as a function of eccentricity. Similarly, the amplitudes of the first negative and positive peaks of the first-order MERG waveform were reduced with age, and the pattern of reduction followed a similar eccentricity dependency. The aging-related changes in the MERG waveform may be due to slowed temporal adaptation in the aged retina.