OPTIC NEURITIS - VARIATIONS IN TEMPORAL-MODULATION SENSITIVITY WITH RETINAL ECCENTRICITY

Temporal modulation sensitivity functions were measured centrally and at eccentricities of 2.5°, 5° and 10° in the temporal visual field of 12 patients with recovered optic neuritis and in a group of matched normal controls. A circular, spatially uniform stimulus of 1° angular subtense was presented with sinusoidal modulation at 5, 8, 14 and 23 Hz. The general pattern of results in patients was a loss of sensitivity relative to normal controls at all temporal frequencies at 0° and 2.5° eccentricity, with rather greater losses occurring at the medium-to-lower temporal frequencies. At 5° eccentricity, the losses were confined to medium temporal frequencies only, and at 10° eccentricity there was no significant loss at any temporal frequency. These findings may be explained by a greater vulnerability of optic nerve fibres of small diameter to the effects of demyelinating disease. © 1990 Oxford University Press.