To determine if dimming the light to 1 eye affects baseball hitting (motion-in-depth) and if binocular interaction influences the ability to hit a baseball.
The ability to hit baseballs in a batting cage was measured under conditions of (1) no filter before either eye, (2) neutral density filters before both eyes, and (3) a neutral density filter before 1 eye, while viewing with both eyes. Batting scores were based on the number of hits, fouls, and misses.
A neutral density filter of 0.6 optical density before both eyes had no significant effect on batting ability compared with no filter (87% vs 94%). While viewing binocularly, a filter before 1 eye caused a significantly greater reduction in hitting scores than when the filter was placed before the opposite eye (36% vs 80%). This greater effect of 1 eye on hitting scores denotes an ocular preference or dominance within the motion stereopsis system. The eye associated with the greater reduction in hitting ability when dimmed by a filter was termed the dominant eye for motion stereopsis. In comparison with placing 0.6-optical density filters before both eyes, the same filter before the dominant eye reduced hitting ability (36% vs 87%), but when the filter was placed before the nondominant eye, the hitting ability was not significantly reduced (80% vs 87%). The batting scores decreased as filter densities increased from 0.3to 0.6-optical density, and the effect was significantly more for the dominant eye than for the nondominant eye.
Binocular vision contributes to the precise localization of a pitched baseball, and one eye influences baseball hitting more than the other eye. The motion-in-depth channel (baseball hitting) shares a sensitivity to unequal binocular illumination with the sidewaysmotion channel (Pulfrich phenomenon). The timing of the impulses conducted from the eyes appears to be critical for the precise localization of objects processed by either the motion-in-depth (baseball hitting) or the sideways-motion (Pulfrich phenomenon) channels.
Hofeldt AJ, Hoefle FB, Bonafede B. Baseball Hitting, Binocular Vision, and the Pulfrich Phenomenon. Arch Ophthalmol. 1996;114(12):1490–1494. doi:10.1001/archopht.1996.01100140688008
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