Abstract

In some optic neuritis (ON) patients, the relative sensitivity loss for stationary versus moving targets (statokinetic dissociation, or SKD) has been attributed to selective losses of mechanisms sensitive to low temporal frequency modulation. Our work suggests that ON patients exhibiting SKD show relatively good sensitivity to moving targets over a range of angular velocities (1-8°/s) despite substantial losses in flicker sensitivity at all frequencies (2-20 Hz). This finding is based on a comparison of the results of automated static, kinetic, and flicker perimetry in ON patients with SKD. In many cases, severely reduced sensitivity to flicker occurred within the region where moving targets were readily detected. Because the apparent superiority of motion sensitivity can occur in spite of large losses in flicker sensitivity, the former maybe based on spatial, rather than temporal, abnormalities. This abnormal spatial summation was confirmed by comparing static perimetry results for size III (0.43°) and size V (1.72°) targets. Thus, both temporal and spatial abnormalities are present in ON patients with SKD. Contrary to previous hypotheses, SKD does not appear to be based on a selective loss of mechanisms sensitive to low temporal frequency modulation. Spatial summation abnormalities may form the primary component underlying SKD.

© 1990 Optical Society of America