FLASH AND PATTERN VEPs: EXAMPLES OF CASES OF HYSTERICAL AMBLYOPIA AND PROVOKED VISUAL IMPAIRMENT (UHTHOFF'S SIGN)

Pattern visual evoked potentials in cases of ambiguous acuity loss

Thirty patients were referred to our visual evoked potential laboratory with complaints of profound acuity loss in one or both eyes. However, the objective ophthalmologic findings were normal, including pupillary reaction, and anterior segment and fundus examinations. Transient visual evoked potentials to a 2.3-c/deg sinusoidal grating pattern were found to be present in 26 of these 30 patients. Visual evoked potentials may be used as a measure of afferent pathway integrity.

Visual changes mediated by beer in retrobulbar neuritis--an investigative case report

A patient with established retrobulbar neuritis and Uhthoff's phenomenon who claimed that his visual acuity improved after drinking beer was assessed by detailed quantitative psychophysical tests. Studies of electrophysiological responses and biochemical levels of blood serum before and after drinking on several occasions were also made. The results of tests of contrast sensitivity, spectral sensitivity, flicker sensitivity, and visually evoked potential confirmed his observation. Some mechanisms for this phenomenon are considered.