West Roger W
Oklahoma College of Optometry, Northeastern State University, Tahlequah, Oklahoma 74464, USA.
Optom Vis Sci. 2011 Feb;88(2):303-11. doi: 10.1097/OPX.0b013e3182059ef3.
Much of the previous research on the perceived direction of gaze has not specified eye color or pupil visibility. This study tests whether the lightness or darkness of a gazer's irises (typically brown vs. blue) affects their perceived direction of gaze.
Twenty-five observers judged the direction of horizontal gaze from a model whose LCD-imaged head gazed toward points on the plane of the observer's face. The model's head was displayed with its natural brown irises and also with its irises digitally altered to look blue without pupils, blue with centered pupils, and blue with nasally decentered pupils. True gaze location was compared with the judged gaze location for each type of iris.
For all iris types, observers judged that monocular gaze was biased outward from its true direction for all gaze locations, including central, whereas binocular gaze was close to centered and had a greater slope. Blue eyes with no pupil and blue eyes with a centered pupil exaggerated this perceived outward deviation for monocular gaze but binocular gaze remained the same. When the pupils were nasally decentered by a typical amount, straight monocular as well as binocular gaze appeared to be centered.
The direction of monocular gaze from eyes that differ in the darkness of their irises is perceived differently, and, within the blue irises, small differences in pupil centration made surprisingly large differences in the perceived directions of gaze.
先前关于感知注视方向的许多研究并未明确眼睛颜色或瞳孔可见性。本研究测试注视者虹膜的深浅（通常为棕色与蓝色）是否会影响其感知的注视方向。
25名观察者从一个模型判断水平注视方向，该模型的液晶成像头部注视观察者面部平面上的点。模型头部显示其自然的棕色虹膜，同时其虹膜经数字处理后看起来为无瞳孔的蓝色、有居中瞳孔的蓝色以及有鼻侧偏心瞳孔的蓝色。将每种虹膜类型的真实注视位置与判断的注视位置进行比较。
对于所有虹膜类型，观察者判断单眼注视在所有注视位置（包括中央位置）都偏离其真实方向向外偏斜，而双眼注视接近居中且斜率更大。无瞳孔的蓝眼睛和有居中瞳孔的蓝眼睛会夸大单眼注视的这种感知向外偏差，但双眼注视保持不变。当瞳孔鼻侧偏心达到典型程度时，单眼直视以及双眼注视看起来都居中。
不同虹膜深浅的眼睛的单眼注视方向被感知的情况不同，并且在蓝色虹膜范围内，瞳孔中心位置的微小差异在感知注视方向上产生了惊人的巨大差异。
