Pardhan Shahina, Gonzalez-Alvarez Carmen, Subramanian Ahalya
Vision and Eye Research Unit, Postgraduate Medical Institute, Anglia Ruskin University, Cambridge, United Kingdom.
Optom Vis Sci. 2012 Apr;89(4):426-34. doi: 10.1097/OPX.0b013e31824c1b89.
The aim of this study is to investigate whether subjects with central visual impairment (VI) show different reaching and grasping behavior for targets of different contrasts compared with visually normal age-matched subjects.
Reaching and grasping performance was measured in 14 subjects with VI and 14 normal subjects. Subjects were asked to pick up a cylindrical target. Three different targets were used: black (low contrast), white (high contrast), and transparent, placed against a black background. A motion analysis system (Vicon 460) recorded and reconstructed the hand and finger movements.
Significantly longer onset times, total movement duration, and time after maximum grip aperture were obtained for subjects with VI compared with normal subjects (p < 0.002). No significant differences existed in maximum velocity and grip aperture between the two groups for any of the targets.
Subjects with VI took longer to initiate and to complete the movement. Maximum velocity and grip aperture were not different suggesting that once the target was "seen" by subjects with VI performance was similar to normal subjects. Time after maximum grip aperture was longer in subjects with VI indicating the need for "online" modifications in these subjects. Contrast sensitivity was significantly correlated to more indices than visual acuity.
本研究旨在调查与视力正常的年龄匹配受试者相比，患有中枢性视力障碍（VI）的受试者对不同对比度目标的伸手和抓握行为是否存在差异。
对14名患有VI的受试者和14名正常受试者的伸手和抓握表现进行了测量。要求受试者拿起一个圆柱形目标。使用了三种不同的目标：黑色（低对比度）、白色（高对比度）和透明的，放置在黑色背景上。一个运动分析系统（Vicon 460）记录并重建了手部和手指的运动。
与正常受试者相比，患有VI的受试者的起始时间、总运动持续时间以及最大抓握孔径后的时间显著更长（p < 0.002）。对于任何目标，两组之间的最大速度和抓握孔径均无显著差异。
患有VI的受试者开始和完成运动所需的时间更长。最大速度和抓握孔径没有差异，这表明一旦患有VI的受试者“看到”目标，其表现与正常受试者相似。患有VI的受试者在最大抓握孔径后的时间更长，这表明这些受试者需要“在线”调整。对比敏感度与比视力更多的指标显著相关。
