Normal saccadic velocities

Although it is desirable that each laboratory establish its own normal values, this study examines the comparability of results obtained in two different laboratories with the Tracoustics RV-275 recorder. Twenty neurologically normal subjects, ages 8 to 32 years, with no history of strabismus or ocular muscle surgery, were studied. Horizontal saccades of 20 degrees across the midline, with fixation by the recorded and by the non-recorded eye, were observed. Peak velocity determinations distributed normally and ranged from 281 to 541 (mean and SD = 393 ± 50) degr/sec. Mean velocities recorded during non-fixation were similar to those recorded during fixation. Based on these results, a twenty degree peak horizontal saccadic velocity of less than 300 degr/sec using this equipment is highly likely to be abnormally slow, irrespective of antagonist or symmetric movement comparisons; the latter cannot be relied on in cases of bilateral or multiple rotation abnormalities. The recording sequence may influence antagonist and symmetric pair comparisons.