Centre for Vision and Eye Research, Queensland University of Technology, Queensland, Australia.
Danderyd, Sweden.
Ophthalmic Physiol Opt. 2022 Mar;42(2):384-392. doi: 10.1111/opo.12932. Epub 2021 Dec 12.
Human peripheral detection performance is affected by optical factors such as defocus and higher order aberrations. From optical theory, we would expect defocus to produce local depressions (notches) in the contrast sensitivity function (CSF). However, such notches have not been observed in peripheral vision, and it is unknown whether human peripheral vision can detect local depressions (notches) in the CSF, such as those produced by monochromatic defocus when all monochromatic ocular aberrations are corrected. The purpose of the study was to identify such notches.
Participants were three adult emmetropes. Following full adaptive optics correction, on-axis and 20° nasal visual field detection CSFs in monochromatic light were measured for the right eye with a 7 mm diameter pupil, both without and with ±2 D defocus, and with separate determinations for horizontal and vertical gratings. Defocused CSFs were compared with predictions based on theoretical modulation transfer functions.
Notches in the monochromatic defocused CSFs were identified for peripheral vision at optically predicted spatial frequencies with other monochromatic ocular aberrations corrected, provided that there was adequate spatial frequency sampling. The spatial frequencies of notches were similar to those predicted from optical theory, but their depths (0.3 to 0.9 log unit) were smaller than predicted.
With fine spatial frequency sampling, notches were identified in defocused monochromatic CSFs when all other monochromatic ocular aberrations were corrected, both on-axis and at 20° eccentricity. Unless recognised as such, notches may contribute to noise in through-focus detection measurements of peripheral visual performance.
人类的周边视觉检测性能会受到离焦和高阶像差等光学因素的影响。根据光学理论，我们预计离焦会导致对比敏感度函数（CSF）出现局部凹陷（缺口）。然而，在周边视觉中尚未观察到这种缺口，并且尚不清楚人类的周边视觉是否能够检测 CSF 中的局部凹陷（缺口），例如当所有单色眼像差都得到校正时，单色离焦产生的缺口。本研究的目的是确定这种缺口。
参与者为三名成年正视眼者。在完全自适应光学校正后，使用直径为 7 毫米的瞳孔，分别在右眼上测量了轴向和 20°鼻侧视野的单色光检测 CSF，既不带有也带有±2 D 的离焦，并分别对水平和垂直光栅进行了测定。将离焦 CSF 与基于理论调制传递函数的预测值进行了比较。
在其他单色眼像差得到校正的情况下，当提供足够的空间频率采样时，在光学预测的空间频率处，周边视觉的单色离焦 CSF 中可以识别出缺口。缺口的空间频率与光学理论预测的相似，但深度（0.3 至 0.9 个对数单位）比预测的要小。
在进行精细空间频率采样时，当校正了所有其他单色眼像差时，无论是在轴向还是在 20°偏心度，都可以在单色离焦 CSF 中识别出缺口。除非将其识别为缺口，否则这些缺口可能会对周边视觉性能的聚焦检测测量中的噪声产生影响。
