Agrocampus Ouest, Centre d'Angers, Angers, France.
The Neuropsychological Laboratory CNS-Fed, Paris, France.
Eur J Neurosci. 2021 Mar;53(5):1473-1486. doi: 10.1111/ejn.14929. Epub 2020 Oct 16.
As the eyes continuously move in 3D space, they rarely converge at the exact depth of the plane even when fixating a 2D image or computer screen. Rather, the lines of gaze measured by eye movement recordings show some misalignment so-called fixation disparity. Fixation disparity occurs in front of or behind the plane, and the eyes may also be lagged vertically. For those reasons, vision research requires mathematical tools to calculate where exactly the lines of gaze cross the stimulus plane. Seminal research on vergence eye movements targeting stimuli lying on isovergence curves has been content with simple computation of the difference between the two eye rotation angles. Recently, the need of new calculations has emerged with the increasing use of eye-trackers providing the eye coordinates on a computer screen. Previous studies have made this attempt but with restrictions. We introduce here a complete calculation of fixation disparity in 3D space allowing vision researchers to study the precision of gaze regardless of the stimulus location in 3D space and of whether the eyes lag horizontally and/or vertically.
当眼睛在 3D 空间中连续移动时，即使注视 2D 图像或计算机屏幕，它们也很少会聚在平面的精确深度上。相反，通过眼动记录测量的注视线显示出一些失准，即所谓的注视差异。注视差异发生在平面的前面或后面，眼睛也可能在垂直方向上滞后。出于这些原因，视觉研究需要数学工具来计算注视线到底在哪里穿过刺激平面。针对位于共面曲线上的刺激的会聚眼动的开创性研究，一直满足于计算两个眼球旋转角度之间的差异的简单计算。最近，随着越来越多地使用提供计算机屏幕上眼球坐标的眼动追踪器，出现了对新计算的需求。以前的研究已经尝试过，但有一些限制。我们在这里介绍了一种完整的 3D 空间中注视差异的计算方法，使视觉研究人员能够研究无论刺激在 3D 空间中的位置如何，以及眼睛是否在水平和/或垂直方向上滞后，都能精确地注视。
