Degradation of Visual Pursuit During Sustained +3 Gz Acceleration


  1. Cheung, B.
  2. Hofer, K.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
During positive acceleration, there is a diminshed flow of blood to all regions above the heart. This is manifested by the commonly described loss of peripheral vision, greyout and blackout, which have been investigated extensively. The ability to select appropriate scanning patterns and to efficiently process visual information is one of the important determinants of scan effectiveness. This study investigates the performance of the smooth pursuit system under sustained +3 Gz before any signs of loss of vision. Eleven subjects with no known oculomotor and vestibular anomalies participated in the study. Horizontal and vertical pursuit at amplitudes of 10 and 20 degrees were investigated in each of the subjects over 4 separate days. During each test session, pursuit targets of a predictable sine wave, oscillating at 0.2, 0.4, 0.8, 1.2 and 1.6 Hz were presented to the subjects in a andom order. Horizontal and vertical eye movements wer erecorded using the El-Mar eye tracking system. The subjects were tested in 4 trials: 1) at 1 G before exposure to increased acceleration; 2) during sustained _3 Gz; 3) immediately after the +3 Gz exposure; and 4) 5 min after the +3 Gz exposure. TRUNCATED
Eye movements;Ocular pursuit
Report Number
DCIEM-97-P-21 — Reprint
Date of publication
01 May 1999
Number of Pages
Reprinted from
Aviation, Space, and Environmental Medicine, vol 70, no 5, 1999, p 451-458
Hardcopy;Document Image stored on Optical Disk

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