Abstract
Abstract: :
Purpose: The importance of peripheral stereopsis is frequently recognized in daily life such as when going down the stairs. However, commercially available stereo test can only detect macular stereoptosis and fusion. We developed a new test to evaluate peripheral stereopsis. Methods: Twenty subjects with normal macular function were studied. We developed a new software to generate the 3D target with Macromedia Director. The target was projected on the large screen using two projectors (3D-vision, Sanyo, Osaka). Subject can see 3D images by wearing polarized glasses. We displayed a fixation target without disparity and circular target with disparity. Circular target was projected with the angle 5°, 10°, 20°, 25°, 30°, or 40° temporal from the fixation target. Disparity of target was set 0, 640’’, 1300’’, 1°, or 3°. Size of target was set with radius of 2.9°, 4.3°, 5.7°, 7.1°, or 8.5°. We recorded changing target position, parallax, and size. We also investigated motion stereopsis test using circular target changing the disparity 1300’’ per second linearly from 0 to 1° (n=13). We compared static stereopsis with motion stereopsis by recording maximum visual angle they showed. Results: Using mimimum target size and minimum disparity, within 10°visual angle all subjects showed stereopsis, 16 (80%) of them at 20° visual angle, 7(35%) of them at 25°, and none at 40°. But with maximum disparity (3°), 12(60%) of them showed with 40° visual angle. Using the target with mimimum disparity, and with all visual angles, the number of subjects who showed stereopsis was correlated with target size. (p=0.0017) Using minimum target size, the number of subjects who showed motion stereopsis was smaller than these with static stereopsis. (p=0.0262) But with maximum target size, the differentce was not significant. (p=0.2945) Conclusions: In this study, it was demonstrated that the peripheral stereopsis was notably decreased with visual angle beyond 20°. Peripheral stereopsis was also well correlated with target size. Dynamic target didn’t make pheripheral stereopsis easier especially for target with small size.
Keywords: motion-3D • strabismus: diagnosis and detection • visual development