立体视锐度的测量

THE MEASUREMENT OF STEREOSCOPIC ACUITY

视差只在一定大小范围内才能产生体视感觉。对５名体视感觉正常者和一名体视感觉欠缺者做心理物理试验并记录视觉诱发电位（ＶＥＰ）。结论如下：（１）交叉视差产生体视感觉的视差下限阈值约为２５秒；非交叉视差产生体视感觉的视差下限阈值约为３５秒。（２）改变视差大小的方法不同对这个阈值有影响。视差由大到小改变比由小到大改变，这个视差下限阈值要小，两者差别约为１０秒至２０秒。（３）体视欠缺者产生体视感觉的视差下限阈值约为６０秒。（４）使用不同形式的立体图对这个阈值不同，对于随机点立体图对，产生体视感觉下限阈值约为６０秒。（５）当视差大于１２０秒时的ＶＥＰ呈现规律变化。（６）体视欠缺者的ＶＥＰ与正常者比较呈现较大的差别。

Disparity which within a certain range can form stereoscopic perception. VEPs and psychophysical experimentS obtained from sir subjects with different stereoscopic pair was analyzed. The results indicate that : A) The least degree of crossing disparity that can form stereopsis is about 25' and disparity is 35' for non-crossing. B) The least degree of disparity is effected by changing dispaity with different way. The difference is about 10'-20'. C) The least degree of disparity is about 60' when used RDS. D) The least degree of disparity is about 60' for the abnormal. E) VEPs keep a regular change, when disparity more than 120'.F) The VEPs obtained from person who have poor stereosis present some difference as compared with that from the normal.