STUDY OF STRABISMUS USING A VIRTUAL REALITY SYSTEM

视觉系统的功能是将三维世界感知为二维视网膜图像，并使用双目视差、大小、阴影、阴影、纹理、运动等立体按键重建三维世界。本研究的目的是阐明这些按键中的哪些是正常或斜视患者在哪些条件下使用的。在头盔显示器上每隔65 mm安装两台与LCD屏幕视场相似的彩色摄像机。每个摄像头都连接到一个LCD屏幕上，因此投射的图像与受试者看到的图像相同。佩戴头盔后，受试者可以正常观看。改变摄像机与屏幕的连接方式，产生正常双眼视差、反向视差或非视差，观察正常和斜视受试者。立体视觉测试在正常和反向双眼视差下进行，正常受试者感觉正常立体视，双眼视差正常。对于书籍、面孔、课桌、椅子等被试来说，能够正确地识别出具有反向视差的物体的立体形状。当他们看到绳索等复杂的东西时，他们感到困惑，在这种情况下，他们没有通过环钩测试。斜视受试者几乎可以正确地识别正常视差和反向视差的立体形状。只有当环在正常视差和反向视差条件下移动时，他们才能通过环和钩测试。这表明斜视患者比正常人更多地使用单眼立体视钥匙来补充他们双眼立体视知觉的不足。

The function of the visual system is to perceive the three dimensional world as two dimensional retinal images and to reconstruct it using stereoscopic keys such as binocular parallax, size, shadows, shades, textures, motion, etc. The purpose of this study is to clarify which of these keys are used under which conditions by normal or strabismic patients.A head mounted display (HMD) was made, which was composed of liquid crystal display panels (LCD) and eye position/movement monitoring systems using infrared video camera. Two CCD color video cameras whose field of vision was similar to those of the LCD screens, were attached to the HMD at intervals of 65 mm. Each camera was connected to one LCD screen so that the image projected was the same as the subjects were seeing. Wearing the HMD the subjects could see normally. Changing the connections between video cameras and screens, the normal binocular parallax, reversed parallax or non parallax were created.Normal and strabismic subjects were investigated. Stereoscopic tests were performed under normal and reversed binocular parallax.Normal subjects felt normal stereopsis with normal binocular parallax. The could correctly recognize the stereoscopic shape with reversed parallax of the objects were familiar for the subjects such as books, faces, desks or chairs. They were confused when they saw complicated things such as tangled ropes, and they failed ring and hook test in this condition. Strabismic subjects could almost correctly recognize the stereoscopic shape with both normal and reversed parallax. They passed the ring and hook test only when the ring was moving in both normal and reversed parallax conditions.It is suggested that strabismic patients used monocular stereoptic keys more than normal persons to supplement their lack of binocular rarallax perception.