Purchase this article with an account.
Nick F Fogt, Marc A Burcham; Gaze tracking of pitched balls through apertures. Invest. Ophthalmol. Vis. Sci. 2014;55(13):2579.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
It has been shown that experienced baseball players tend to move the head significantly and the eyes very little when tracking pitched balls. Attempting to track pitched balls through apertures in front of the eyes might force individuals to adopt the pattern of head-eye coordination used by experienced players. The purpose of this experiment was to determine whether individuals would adopt the appropriate pattern of head and eye coordination (head movement with rotational vestibulo-ocular reflex (RVOR) suppression) to view pitched balls through small apertures.
Data were gathered from 10 subjects with variable baseball experience. Subjects viewed tennis balls (76mph) thrown by a pneumatic pitching machine 43.6ft away. Head movements (inertial sensor) and (left) eye movements (video tracker) were recorded. Head, eye, and ball positions were synchronized by software. Two tracking trials (50 pitches each) were utilized. In the first trial (no-aperture/NA condition), subjects attempted to keep their eyes on the ball as long as possible. In the second trial (aperture/A condition), subjects attempted to keep the eyes pointed at the ball while wearing small (3.3deg) apertures centered over both eyes.
Blink-related data were discarded. Data were analyzed at 300ms after pitch release (ball 8 ft from the subject). Head rotation, eye rotation, and gaze (head+eye) errors were calculated. Mean head rotations (mean NA = 19.4±-9.8deg) were always in the direction of the ball and always much larger than mean eye rotations (mean NA = 1.8±4.8deg) in both conditions. Depending on the subject, mean eye movements could be in the direction of the ball, opposite the ball, or near zero. Four of 10 subjects made mean eye movements less than 1.7deg (half-angle of apertures) with the apertures. There were no statistically significant (p>0.05) differences in the NA and A conditions for mean head movements, mean eye movements, or mean gaze errors (paired t-test).
Four of 10 subjects suppressed the RVOR sufficiently to maintain the visual axis through the aperture. However, there were no statistically significant differences between the mean head movements, mean eye movements, or mean gaze errors in the NA and A conditions. Taken together, these results suggest that the apertures resulted in no consistent changes in head and eye movements. Subjects generally showed similar head and eye tracking behaviors with and without the apertures.
This PDF is available to Subscribers Only