Eye tracking performance variability in a homogeneous population.

Pursuit tracking eye movements were recorded and analyzed from a group of US Air Force Pilot Candidates (PCs). The PCs ranged in age from 21 to 27 with a median age of 23. All were college graduates and recently passed a Flying Class I physical exam. These PCs comprise a highly motivated, intelligent group of young subjects. Pursuit tracking was assessed by having the subjects track a small spot of green light moving sinusoidally in the horizontal plane at frequencies from 0.2 to 1.0 Hz in 0.2 Hz increments. Peak-to-peak target amplitude was 40 degrees. Eye movements were recorded using an infrared reflectance device. Eye movements were separated into smooth pursuit (SP) and saccadic (SA) components. Tracking performance was evaluated by computing the gain and asymmetry of the SP component and the percentage of tracking movements contributed by the SA component. Both mean values and variance of the tracking performance of the PCs were not found to be statistically different from a group consisting of both flying and nonflying Air Force personnel.