Electrophysiological tests of vision measure the electrical activity generated by the eye, the optic pathways, and the visual cortex, and thus provide important diagnostic information to the clinical ophthalmologist. Traditionally, these electrophysiological tests involved stimulation of relatively large areas of the retina.1 For example, for the standard electroretinogram (ERG) and the flash visual evoked potential (VEP) tests, the entire retina is illuminated. Other tests, such as the pattern ERG and VEP tests, use a stimulus that typically exceeds 15° in diameter. The size of the stimuli used for these tests presents a problem if the clinician is interested in the local topography of the damage to the retina or optic nerve, as is often the case in neuro-ophthalmology. Although ERG and VEP responses can be elicited to relatively small stimuli using traditional measures, each retinal area had to be be tested separately. Thus, if a clinician wanted a topographical map, the time needed to obtain multiple responses was prohibitive.