Abstract
Previous researchers (e.g., Owens & Leibowitz, 1980) have shown large individual differences in measures of the resting states of accommodation (dark focus; DF) and vergence (dark vergence; DV). However, no useful relationship has been found between these two resting measures. The present study investigated whether either of these measures were related to the third resting state of eyes, namely resting gaze elevation (in the dark; GE). All three resting states were measured in the dark from 74 college-aged participants. DF was measured using a Seiko WV-500 autorefractor, DV was measured in using a Vergamatic nonius alignment technique, and GE was measured using a briefly presented light and a modified binary search psychophysical procedure. No significant correlations were found between the three resting states: r (DF/DV) = .017, r (DF/GE) = −.001, and r (DV/GE) = −.123. The last correlation was somewhat surprising given that both involve the extra-ocular muscles and perhaps are related to the Heuer effect.
To investigate whether DF, DV, or GE were related to the preferred computer monitor position for a given individual, a subset of the participants (N = 25) were asked to play a computer game of mini-golf. A 15-inch Dell flat screen monitor was mounted on a fully adjustable Ergotron mounting arm. Participants were able to position the monitor precisely where they wanted (viewing distance and monitor height) and could change the position during the game if desired. Directly after playing the game, the participant's viewing distance and monitor viewing angle (from eye level) were measured. Monitor viewing distance was not related to DF or DV distances. A correlation of r = .297 was found between GE and the monitor viewing angle but did not reach significance due to sample size. It did indicate that participants with lower resting gaze elevations tended to prefer a lower monitor location.