Saccadic velocities of horizontal rectus muscles in twenty-five normal humans

We measured horizontal saccadic velocities for 20 degrees saccades in 25 normal humans. Percent differences for various muscle pairs were calculated for each subject. For example, percent differences of the antagonist muscles averaged +4.9 +/- 10% and percent differences of symmetrical muscles averaged -9.2 +/- 9%. This percent difference type of data, previously unreported, allows more accurate detection of pathology in a given patient than comparison of a single saccadic velocity with an average of normals because of large intersubject variability. We also found ways to make the performance of the test more convenient and the calculations significantly more accurate (0.001). These will be described. The average speed of a horizontal rectus saccade was 396 +/- 53 degrees/sec.