Schor Clifton M, Maxwell James S, McCandless Jefrey, Graf Erich
University of California at Berkeley, School of Optometry, Berkeley, California 94720, USA.
Ann N Y Acad Sci. 2002 Apr;956:297-305. doi: 10.1111/j.1749-6632.2002.tb02828.x.
Vergence eye alignment minimizes horizontal, vertical, and cyclodisparities to optimize stereo-depth perception. Only the horizontal component of vergence is under voluntary control. Couplings with voluntary version and horizontal vergence guide vertical vergence and cyclovergence. Can these couplings be modified in response to sensory demands on binocular vision? We have modified vertical vergence and cyclovergence in response to optical changes in disparity. Vertical vergence was stimulated with aniseikonic lenses that exaggerated vertical disparity in tertiary gaze. Vertical vergence adapted in an hour to produce nonconcomitant changes in vertical phoria that varied with vertical eye position in tertiary gaze. Cyclovergence was stimulated with cyclodisparities that varied with gaze elevation and convergence angle. Cyclovergence adapted within 2 hours to produce nonconcomitant changes in cyclophoria that varied with gaze elevation and convergence. The adaptive couplings for vertical vergence and cyclovergence are modeled as a combination of passive orbital mechanics and active gain control of the vertical recti and obliques. Vergence adaptation is a calibration process that adjusts the innervation for horizontal, vertical, and torsion components of vergence to the physical constraints set by the extraocular muscles and orbital connective tissues. Passive orbital mechanics simplify the neural control for precise vertical vergence and cyclovergence that are needed to achieve binocular alignment under open-loop conditions in response to perceived spatial location.
双眼视轴对准可将水平、垂直和旋转视差降至最低，以优化立体深度感知。只有双眼视轴的水平分量受自主控制。与自主的同向运动和水平双眼视轴的耦合引导垂直双眼视轴和旋转双眼视轴。这些耦合能否根据双眼视觉的感觉需求进行修改？我们根据视差的光学变化修改了垂直双眼视轴和旋转双眼视轴。用不等像透镜刺激垂直双眼视轴，该透镜会在第三注视方向上夸大垂直视差。垂直双眼视轴在一小时内适应，从而产生与第三注视方向上的垂直眼位变化相关的非共轭性垂直隐斜变化。用随注视高度和集合角度变化的旋转视差刺激旋转双眼视轴。旋转双眼视轴在两小时内适应，从而产生与注视高度和集合相关的非共轭性旋转隐斜变化。垂直双眼视轴和旋转双眼视轴的适应性耦合被建模为被动眼眶力学与垂直直肌和斜肌的主动增益控制的组合。双眼视轴适应是一个校准过程，可将双眼视轴的水平、垂直和扭转分量的神经支配调整到由眼外肌和眼眶结缔组织设定的物理约束条件。被动眼眶力学简化了神经控制，以实现精确的垂直双眼视轴和旋转双眼视轴，这是在开环条件下响应感知到的空间位置实现双眼对准所必需的。
