Heuer H, Owens D A
Department of Psychology, Philipps-Universität Marburg, FRG.
Perception. 1989;18(3):363-77. doi: 10.1068/p180363.
With horizontal gaze, the resting posture of binocular vergence typically corresponds to a distance of about 1 m. The effect of vertical direction of gaze on this basic resting posture was investigated. The dark vergence of twenty-four subjects was measured while they fixated a dim monocular light-point at vertical directions ranging from -45 degree (lowered) to +30 degrees (elevated). In one condition, gaze was varied by changes in eye position with the head held upright; in a second condition, gaze was varied by changes in head inclination with the eyes held in constant (horizontal) position with respect to the head. In both conditions, dark vergence shifted in the convergent (nearer) direction with lowered gaze and in the divergent (farther) direction with elevated gaze. The effect of varied eye inclination was larger, more variable across subjects, and more stable over time than that of varied head inclination. These findings indicate that multiple mechanisms contribute to gaze-related variations of the resting posture of the eyes. They may help to explain the variations of space perception and visual fatigue that are observed with different gaze inclinations.
在水平注视时，双眼聚散的静止姿势通常对应于约1米的距离。研究了注视垂直方向对这种基本静止姿势的影响。在24名受试者注视一个昏暗的单眼光点时，测量了他们在从-45度（向下）到+30度（向上）的垂直方向上的暗聚散。在一种情况下，通过头部保持直立时眼睛位置的变化来改变注视；在第二种情况下，通过头部倾斜的变化来改变注视，眼睛相对于头部保持在恒定（水平）位置。在这两种情况下，暗聚散在注视降低时向会聚（更近）方向移动，在注视升高时向发散（更远）方向移动。与头部倾斜变化相比，眼睛倾斜变化的影响更大，受试者之间的变化更大，并且随时间更稳定。这些发现表明，多种机制导致了与注视相关的眼睛静止姿势变化。它们可能有助于解释在不同注视倾斜度下观察到的空间感知和视觉疲劳的变化。
