Abstract
Purpose: :
We measured fluctuations of the accommodation and pupil size of both eyes before and after viewing a 3D display to investigate the relationship between the fluctuations and visual fatigue.
Methods: :
Five normal subjects watched a dynamic 3D stimulus on a parallax barrier type 8-inch display (FinePix REAL 3D, FujiFilm Corp. Tokyo). The 3D stimulus was a black asterisk character on white background, and the size was 2 cm on the display. The crossed parallax was shown, and the maximum disparity of the stimulus was 3.8 degrees. The viewing distance was fixed to 60 cm. The subjects watched the stimulus which changed the disparity repeatedly between null and the maximum with 0.25 Hz. The entire stimulus period was 20 minutes. We measured binocular accommodation and pupil size of the subjects while watching a target placed 50 cm from the eye before and after viewing the 3D stimulus using a binocular wavefront sensor (Kobayashi, Applied Optics, 2008). The duration of the measurements was 10 seconds, and frequency was 30 Hz. We repeated the measurements 3 times for each subject before and after the 3D viewing.
Results: :
We did not find any systematic change in the accommodations and pupil sizes after viewing the 3D display in all the subjects. And we did not find any change in fluctuations of the accommodation and the pupil size in four subjects. But in one subject, we found a large accommodative fluctuation one minute after viewing the 3D display. The peak-to-valley of the fluctuation was 0.5 D, and the frequency was 2.7 Hz. The fluctuation of pupil size was correlated to the accommodative fluctuation, but the magnitude was small (less than 0.04 mm in diameter). The fluctuations of both accommodation and pupil size were correlated between both eyes. The fluctuations disappeared 10 minutes after viewing the 3D display.
Conclusions: :
We found the unusual fluctuations of accommodation and pupil size in one subject who claimed fatigue after viewing the 3D display. Although the subject was normal, the fluctuation was similar to those we found in patients with accommodative spasm.
Keywords: accommodation • pupil • binocular vision/stereopsis