Objective measurement of visual function in glaucoma

Of the objective (electrophysiological), functional tests of glaucomatous damage, three hold the most promise. Some evidence suggests that the pattern electroretinogram, the photopic negative response of the electroretinogram, and the multifocal visual-evoked potential can detect early glaucomatous damage, damage that may be missed on static automated achromatic perimetry. However, in their current forms, these tests can supplement, but cannot replace, static automated achromatic perimetry. Further, the multifocal visual-evoked potential is the only one of these tests that supplies topographic information about local damage. In addition, we still lack a complete understanding of the relation between these tests and the underlying damage to ganglion cells. In this context, it has recently been suggested that the signal in the multifocal visual-evoked potential response may be linearly related to the loss of ganglion cells. Finally, more information is needed about these tests from longitudinal or prospective studies.