Fig. 2
Multifocal electroretinography (ERG) in the right (a, c) and left (b, d) eyes in this patient. Multifocal ERG has the advantage of providing a topographic measure of retinal eletrophysiological activity as compared to conventional full-field ERG, which is a technique for evaluating global retinal function. With this technique, 103 local ERG responses are recorded from the cone-driven retina under light-adapted conditions. The trace array is useful for visualizing areas of abnormality, and the 3-D plot shows the overall signal strength per unit area of retina. The trace arrays (a, b) and 3-D plots (c, d) show focally depressed central peak amplitude in the corresponding area of the macular halo (red circle), suggesting decreased foveal visual function. The amplitude of temporal half area in the trace arrays from the right eye (a) was generally decreased because of retinal pigment epithelial atrophy induced by the previous laser treatment