Evaluating stereoacuity with 3D shutter glasses technology.
BACKGROUND
To determine the stereoacuity threshold with a 3D laptop equipped with 3D shutter glasses, and to evaluate the effect of different shape and size of test symbols and different type of disparities to stereoacuity.


METHODS
Thirty subjects with a visual acuity in each eye of at least 0 logMAR and a stereoacuity of at least 32 arcsec (as assessed in Fly Stereo Acuity Test) were recruited. Three target symbols-tumbling "E", tumbling "C", and "□"-were displayed, each with six different sizes representing a visual acuity ranging from 0.5 to 0 logMAR when tested at 4.1 m, and with both crossed and uncrossed disparities. Two test systems were designed - fixed distance of 4.1 m and one for variable distance. The former has disparities ranging from 10 to 1000 arcsec. Each subject completed 36 trials to investigate the effect of different symbol sizes and shapes, and disparity types on stereoacuity. In the variable distance system, each subject was tested 12 times for the same purposes, both proximally and distally (the point where the 3D effect just appears and where it just disappears respectively), and the mean value was calculated from the mean proximal and distal distances.


RESULTS
No significant difference was found among the groups in the fixed distance test system (Kruskal-Wallis test; Chi-square = 29.844, P = 0.715). Similarly, no significant difference was found in the variable distance system (Kruskal-Wallis test; proximal: Chi-square = 5.687, P = 0.338; distal: Chi-square = 5.898, P = 0.316; mean: Chi-square = 6.152, P = 0.292).


CONCLUSIONS
Evaluating stereoacuity using this measurement system was convenient and effective. Changes in target shape and size and disparity types had no significant effect on stereoacuity. It would be helpful to choose optimal targets according to different purposes using computer-assisted 3D measurements.
Department of Optometry, Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, 130041, China. wuhuang@jlu.edu.cn.
Huang
H
Wu
University of Virginia, Charlottesville, VA, USA.
Han
H
Jin
Department of Ultrasonography, First Hospital of Jilin University, Changchun, China.
Ying
Y
Sun
Department of Optometry, Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, 130041, China.
Yang
Y
Wang
Department of Optometry, Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, 130041, China.
Min
M
Ge
Department of Optometry, Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, 130041, China.
Yang
Y
Chen
Department of Optometry, Second Hospital of Jilin University, No. 218, Ziqiang Street, Nanguan District, Changchun, 130041, China.
Yunfeng
Y
Chi
D000328:Adult; D000704:Analysis of Variance; D003867:Depth Perception; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005139:Eyeglasses; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D012684:Sensory Thresholds; D014787:Vision Tests / Q000379:methods*; D015348:Vision, Binocular; D014792:Visual Acuity; D055815:Young Adult
Horizontal disparity; Shutter glasses; Stereopsis