Circular vection in patients with age-related macular degeneration

We have used optokinetic stimulation in patients with unilateral age-related macular degeneration (AMD) and central scotoma to investigate the possible contribution of the central visual field to circular vection (CV). Six patients aged 42-73 years with unilateral AMD and an aged-matched control group of nine elderly adults aged 47-75 years were examined. Monocular visual field defects were verified with the Goldmann perimeter by kinetic perimetry. The device used to induce CV was a random dot pattern projected onto a hemispherical dome with a radius of 75 cm. The pattern was rotated horizontally at a constant acceleration of 1 deg/s2. Monocular stimuli were randomly repeated two to three times in both temporal-nasal (T-N) and nasal-temporal (N-T) directions. The latency of onset of CV was measured for each stimulus presentation. In the age-matched control group the CV latencies varied from 4.2 to 72.0 s. In each case, however, the CV latencies were stable. No significant differences in CV latencies were found between right and left eyes in both stimulus directions (p > 0.05). In patients with AMD, no statistically significant difference in CV latency was found between the affected and unaffected eyes (p > 0.05). Marked central visual field loss in AMD does not significantly impair peripherally induced CV. Our results are compatible with the hypothesis that the peripheral retina dominates CV.