Abstract
Purpose :
It has been reported that people with unbalanced eyes need longer time to reach the optimal stereoacuity than people with balanced eyes. In that study, which applied continuous flashing technique, the ratio of the left and right eyes’ response time was taken as the ocular dominance index (ODI). However, in persons with balanced eyes, two eyes could both respond very quickly and very slowly and still end up with same ODI. It is not clear if, among those persons with balanced eyes, those with respond quicker in ocular dominance test would also have shorter integration time in stereopsis.
Methods :
Ocular dominance was evaluated with continuous flash technique. The tested eye viewed a Gabor patch with increasing contrast, starting from 0%, and the other eye viewed a Mondrian noise with decreasing contrast, starting from 100%, at 1% per 100ms. The time needed for the subject to detect the Gabor patch in the noise was recorded (Tbreak) for the tested eye. Each eye was tested for 50 times. Thirty subjects with two balanced eyes included for analysis and two eyes’ Tbreak values were averaged. The stereopsis was measured with random dots stimulus with varying presenting durations ranging from 25 to 400ms. The stereothresholds versus viewing durations were fitted into an empirical model of quadratic summation, th= Dmin(t-2+Tmin-2)0.5 where th is the stereothreshold at a given viewing duration(t), Tmin is the constant that determines the horizontal position of the function, which is related to the time at which the stereothreshold becomes independent of duration(critical duration). Dmin is the constant that determines the vertical position of the function and is equal to the stereothreshold when t=Tmin.
Results :
The mean Tbreak was 5.06±1.47s, (range from 2.16 to 7.57 s). The mean Tmin value in stereopsis was 132.41±45.01 ms (range from 72.09 to 217.74ms) and the Dmin in stereopsis was 39.65 ± 15.49 arcsec (range from 20.21 to 76.42 arcsec). The Tbreak were significantly associated with the Tmin values in stereopsis (R=0.60, p<0.05). However, Tbreak were not correlated with the Dmins in stereopsis (R=0.06, p=0.54).
Conclusions :
In subjects with balanced eyes, those have quicker response in ocular dominance test tend to have shorter integration time to reach the optimal stereo acuity.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.