Due to the dramatic difference in spatial resolution between the central fovea and the surrounding retinal regions, accurate fixation on important objects is critical for humans. It is known that the preferred retinal location (PRL) for fixation of healthy human observers rarely coincides with the retinal location with the highest cone density. It is not currently known, however, whether the PRL is consistent within an observer or is subject to fluctuations and, moreover, whether observers' subjective fixation location coincides with the PRL. We studied whether the PRL changes between days. We used an adaptive optics scanning laser ophthalmoscope to project a Maltese cross fixation target on an observer's retina and continuously imaged the exact retinal location of the target. We found that observers consistently use the same PRL across days, regardless of how much the PRL is displaced from the cone density peak location. We then showed observers small stimuli near the visual field location on which they fixated, and the observers judged whether or not the stimuli appeared in fixation. Observers' precision in this task approached that of fixation itself. Observers based their judgment on both the visual scene coordinates and the retinal location of the stimuli. We conclude that the PRL in a normally functioning visual system is fixed, and observers use it as a reference point in judging stimulus locations.

中文翻译：

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人类视觉系统中的视网膜和感知的注视点。


由于中央凹和周围视网膜区域之间的空间分辨率存在巨大差异，因此准确注视重要物体对于人类至关重要。众所周知，健康人类观察者注视的首选视网膜位置（PRL）很少与视锥细胞密度最高的视网膜位置重合。然而，目前尚不清楚观察者的 PRL 是否一致或会波动，而且观察者的主观注视位置是否与 PRL 一致。我们研究了 PRL 在几天之间是否发生变化。我们使用自适应光学扫描激光检眼镜将马耳他交叉注视目标投射到观察者的视网膜上，并连续对目标的精确视网膜位置进行成像。我们发现观察者在几天内始终使用相同的 PRL，无论 PRL 与视锥细胞密度峰值位置的位移有多大。然后，我们向观察者展示他们注视的视野位置附近的小刺激，观察者判断刺激是否出现在注视中。观察者在这项任务中的精确度接近于注视本身。观察者的判断基于视觉场景坐标和刺激的视网膜位置。我们得出的结论是，正常运作的视觉系统中的 PRL 是固定的，观察者将其用作判断刺激位置的参考点。