[The characteristics of multifocal electroretinogram in normal subjects in China]

To test the characteristics of multifocal ERG in normal Chinese subjects and to provide reference values in clinical application.

The multifocal ERGs by using VERIS 4.0 visual evoked response imaging system were tested for 42 subjects (48 eyes). Their ages ranged from 11 to 67 years (mean, 40.7 years). The stimulative visual angles subtended plus minus 26.6 horizontally and plus minus 22.1 vertically. Burian-Allen contact lens electrode was used to record the responses from 103 retinal locations in 8 min (16 segments).

With age increasing, the latencies of N(1) wave and P(1) wave delayed, there were statistically significant differences of the latencies between < 50 year group and greater-than-or-equal 50 year group (t > 2.01, P < 0.05), and the amplitude densifies of N(1) wave and P(1) wave decreased with wide inter-individual variation. The amplitude densities of N(1) wave and P(1) wave were greatest at the central fovea, they were (44.88 plus minus 13.30) nV/deg(2), (70.90 plus minus 17.77) nV/deg(2) respectively, the densities reducing towards more peripheral location. The amplitude sum of N(1) wave at the upper retina were greater than that at the lower retina, and the amplitude densities and sums of N(1) wave and P(1) wave at superior-temporal quadrant were greater than that at inferior-nasal quadrant.

Our results suggest multifocal ERG be able to reflect the visual function at different retinal locations correctly and objectively and provide normal reference limits.