Introduction

The pattern electroretinogram (PERG) results from stimulation of the central retina with an isoluminant-reversing black-and-white checkerboard or grating. It arises largely in the inner retina, providing a direct assessment of retinal ganglion cell function. Furthermore, in consideration of the stimulus characteristics, the PERG enables an objective index of macular function. It can therefore play an important role in differentiation between macular and optic nerve dysfunction by facilitating improved interpretation of the cortically generated visual evoked potential (VEP) to a similar stimulus. The reader is referred to recent reviews for further details.^29,42,45