Grasping Deficits and Adaptations in Adults with Stereo Vision Losses
Grasping Deficits and Adaptations in Adults with Stereo Vision Losses
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DOI：
10.1167/iovs.08-3229
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发表时间：
2009-08-01
影响因子：
4.4
通讯作者：
Grant, Simon
中科院分区：
文献类型：
--
作者：
Melmoth, Dean R.;Finlay, Alison L.;Grant, Simon
目的。旨在检查双眼立体视觉的永久性与短暂性降低对触及和抓握（抓握）技能的影响。方法。第一个实验比较了 20 名正常人和 20 名患有长期立体缺陷的成年人（10 名粗视和 10 名视差敏感度无法检测）在使用双眼视觉或仅使用优势眼或非优势眼时的理解能力。第二个实验通过在一只眼睛上放置散焦低倍或高倍镜片来检查暂时模仿正常成年人类似立体视度损失的效果，并与对照（中性镜片）双眼表现进行比较。抓握计划和执行的运动学和误差测量是通过在每种观察条件下进行 40 至 48 次试验，记录受试者在到达、精确抓握和举起圆柱形物体（两种尺寸，四个位置）时记录的首选手的运动来量化的。结果。与双眼视力下降的情况相比，正常情况下的表现更快、更准确，并且在单眼条件下完成得最少。当正常立体视觉永久（方差分析 P < 0.05）或短暂（方差分析 P < 0.001）减少时，运动持续时间就会延长（最多约 100 毫秒），执行抓取时的错误率加倍（方差分析 P < 0.001）。双眼到达的缺陷发生在其最后阶段（最终接近时间延长、速度校正更多、与物体接触的协调性较差），并且通常随着视差敏感性的现有损失而增加。双眼抓握更容易受到立体视度损失的影响，并受到其持续时间的影响。患有长期立体缺陷的成年人在最初接触物体时表现出手指放置的变异性增加，并且他们通过延长（大约 25%）随后应用抓握所花费的时间来适应（方差分析 P < 0.001）。短暂的立体还原导致初始手指位置的系统性变化以及握把位置接触后调整的两到三倍（方差分析 P < 0.01）。结论。高级双目立体视觉对于熟练的精确抓取至关重要。视差敏感度降低会导致抓握点选择不准确，并且会更加依赖来自物体接触的非视觉（感觉）信息来控制抓握稳定性。 （投资眼科可见科学。2009；50：3711-3720）DOI：10.1167/iovs.08-3229
PURPOSE. To examine the effects of permanent versus brief reductions in binocular stereo vision on reaching and grasping (prehension) skills.METHODS. The first experiment compared prehension proficiency in 20 normal and 20 adults with long-term stereodeficiency (10 with coarse and 10 with undetectable disparity sensitivities) when using binocular vision or just the dominant or nondominant eye. The second experiment examined effects of temporarily mimicking similar stereoacuity losses in normal adults, by placing defocusing low-or high-plus lenses over one eye, compared with their control (neutral lens) binocular performance. Kinematic and error measures of prehension planning and execution were quantified from movements of the subjects' preferred hand recorded while they reached, precision-grasped, and lifted cylindrical objects (two sizes, four locations) on 40 to 48 trials under each viewing condition.RESULTS. Performance was faster and more accurate with normal compared with reduced binocular vision and least accomplished under monocular conditions. Movement durations were extended (up to similar to 100 ms) whenever normal stereo vision was permanently (ANOVA P < 0.05) or briefly (ANOVA P < 0.001) reduced, with a doubling of error rates in executing the grasp (ANOVA P < 0.001). Binocular deficits in reaching occurred during its end phase (prolonged final approach, more velocity corrections, poorer coordination with object contact) and generally increased with the existing loss of disparity sensitivity. Binocular grasping was more uniformly impaired by stereoacuity loss and influenced by its duration. Adults with long-term stereo-deficiency showed increased variability in digit placement at initial object contact, and they adapted by prolonging (by similar to 25%) the time spent subsequently applying their grasp (ANOVA P < 0.001). Brief stereoreductions caused systematic shifts in initial digit placement and two to three times more postcontact adjustments in grip position (ANOVA P < 0.01).CONCLUSIONS. High-grade binocular stereo vision is essential for skilled precision grasping. Reduced disparity sensitivity results in inaccurate grasp-point selection and greater reliance on nonvisual (somesthetic) information from object contact to control grip stability. (Invest Ophthalmol Vis Sci. 2009;50:3711-3720) DOI: 10.1167/iovs.08-3229