Variables affecting eye tracking performance.

The effect of age and gender on eye tracking performance was studied in normal healthy subjects. Two measures of tracking performance, phase corrected cross-correlation coefficients and number of catch-up saccades were determined. The cross-correlation measures revealed a differential effect with the elderly men demonstrating significantly better tracking performance than elderly women. An aging effect was found in women and an aging trend in men using the catch-up saccade measure. Other variables influencing tracking performance, in addition to age and sex, were target speed and type of measure. Recognition of this differential effect largely explains the existing controversy as to whether age or sex variables influence tracking performance.