Khan Kiren A, Cufflin Matthew P, Mallen Edward A H
School of Optometry and Vision Science, University of Bradford, Bradford, UK.
Ophthalmic Physiol Opt. 2016 Nov;36(6):649-656. doi: 10.1111/opo.12323.
Blur adaptation occurs when an observer is exposed to continuous defocus. However, it is unclear whether adaptation requires constant defocus, or whether the effect can still be achieved when the adaptation period is interrupted by short periods of clear vision.
The study included 12 emmetropes and 12 myopes. All observers wore full refractive correction throughout the experiment. 1D and 3D of myopic defocus was introduced using spherical convex lenses. An automated system was used to place the blurring lens before the RE for varying periods of blurred and clear vision during adaptation. Participants watched a DVD at 3 m during each 15 min trial. Visual acuity was measured using Test Chart 2000 before and after adaptation.
Blur adaptation occurs to varying degrees depending on the periods of incremental blur exposure. Significant improvements in defocused visual acuity occur with continuous blur, equal blur and clear periods, as well as for longer blur periods. However, longer clear periods showed reduced adaptation and this trial is significantly different to the other three trials for both defocus levels (p < 0.001). No refractive group differences were observed for neither 1D nor 3D defocus (p = 0.58 and p = 0.19 respectively).
Intervening periods of clear vision cause minimal disruption to improvements in defocused visual acuity after adaptation, indicating that blur adaptation is a robust phenomenon. However, when the exposure to clear vision exceeds the defocused periods, adaptation is inhibited. This gives insight into the effects of real-world tasks on adaptation to blur.
当观察者暴露于持续的散焦状态时会发生模糊适应。然而，尚不清楚适应是否需要持续的散焦，或者当适应期被短暂的清晰视觉打断时，这种效果是否仍然可以实现。
该研究纳入了12名正视者和12名近视者。所有观察者在整个实验过程中均佩戴完全屈光矫正眼镜。使用球凸透镜引入1D和3D近视性散焦。在适应过程中，使用自动化系统在右眼前方放置模糊镜片，以实现不同时长的模糊和清晰视觉。在每次15分钟的试验中，参与者在3米处观看DVD。适应前后使用Test Chart 2000测量视力。
根据增加的模糊暴露时长，模糊适应会在不同程度上发生。持续模糊、相等的模糊和清晰时长以及更长的模糊时长都会使散焦视力有显著改善。然而，更长的清晰时长显示出适应程度降低，并且在两种散焦水平下，该试验与其他三项试验均有显著差异（p < 0.001）。对于1D和3D散焦，均未观察到屈光组间差异（分别为p = 0.58和p = 0.19）。
清晰视觉的干预期对适应后散焦视力的改善造成的干扰最小，这表明模糊适应是一种稳健的现象。然而，当清晰视觉的暴露时间超过散焦时间时，适应会受到抑制。这为现实世界任务对模糊适应的影响提供了见解。
