CONTRAST SENSITIVITY AND OCULAR TREMULOUS MICRO-MOTIONS: A MODEL STUDY OF CHANGED GRAVITY EFFECTS ON VISUAL PERCEPTION

Visual contrast sensitivity and tremulous micro-movements of eyes were evaluated in 10 human subjects (mean age 30.8 ± 4/6 yrs) volunteered for dry immersion (DI) as a model of the physiological effects of microgravity. Contrast sensitivity was registered using visocontrastmetry with presentation of the Gabor patches with spatial frequency 0.4, 1.0, 3.0, 6.0 and 10.0 c/deg. Amplitude and frequency of eye tremulous movements were measured using a high-frequency optical tweezer. Measurements were performed a day prior to immersion, on DI days 1, 3, 5 and 7, and on the next day after the DI completion. Contrast sensitivity was found altered within both the low and high spatial frequencies; ocular micro-motion amplitudes changed within a wide range. At this point in time, these findings are a step forward in search for a method of objective assessment of the central nervous system functioning in a changed environment.