The time required for U.S. Navy fighter pilots to shift gaze and identify near and far targets.

The speed with which 163 U.S. Navy fighter pilots can shift their line of sight and discriminate high contrast acuity targets was measured. The targets were simultaneously projected onto two screen; one at 18 ft and one at 18 inches in front of the subject's eyes. Subjects were required to fixate first one screen and then as rapidly as possible, shift gaze to the other screen. The minimum exposure duration required to correctly resolve both targets was measured. For 65 subjects, the test target was 1.0 min of visual angle (mva); for 98 subjects the target was 2.0 mva. The major findings are: 1) both Far-to-Near and Near-to-Far mean times significantly slowed with age; 2) there was no significant difference between the Far-to-Near and the Near-to-Far mean times with the oldest subject (44 years of age) excluded; 3) the within-subject standard deviation Far-to-Near increased with age and was significantly greater than the Near-to-Far standard deviation, which did not increase with age; 4) there was a significant correlation between the mean Near-to-Far speeds and the night carrier landing performance of the aviators.