González-Alvarez Carmen, Subramanian Ahalya, Pardhan Shahina
Department of Optometry and Ophthalmic Dispensing, Anglia Ruskin University, Cambridge, UK.
Ophthalmic Physiol Opt. 2007 May;27(3):265-74. doi: 10.1111/j.1475-1313.2007.00476.x.
To investigate how prehensile movements, such as reaching and grasping, are affected by different fields of view when both haptic and visual information are available.
Ten volunteers with normal vision (mean age 24.5 years) participated. Subjects picked up an object with a full monocular field of view (FOV) and with two different sizes of pinholes which simulated a central FOV of 23 degrees and 11 degrees respectively. The Vicon motion analysis system was used to record and reconstruct the 3D-kinematic data. The kinematic parameters measured were total time of the movement, maximum velocity, time to maximum velocity, deceleration time, maximum grip aperture, time to maximum grip aperture and time taken after maximum grip aperture.
Restricting the FOV affected both the transport and grasp components of the movement. The maximum velocity decreased (p = 0.008) and the maximum grip aperture increased (p = 0.003) with both restricted FOV when compared with the full field. The execution or on-line control of both reach and grasp components were also longer (p = 0.005 and p = 0.002 respectively) for the 11 degrees FOV only.
Reducing the FOV to 11 degrees (an absence of peripheral vision) affects the planning and execution of the reach and the grasp component of the movement. Restricting the FOV to 23 degrees of central vision (with some peripheral cues present) affects only the planning of the reach and grasp component of the movement. Peripheral visual cues are therefore more important for the on-line control than for the planning of the movement. The findings of this study have important clinical implications in patients who suffer from ocular diseases in which peripheral vision gradually decreases.
研究当触觉和视觉信息都可用时，诸如伸手和抓握等抓握动作如何受到不同视野的影响。
十名视力正常的志愿者（平均年龄24.5岁）参与了研究。受试者在全单眼视野（FOV）以及分别模拟23度和11度中央FOV的两种不同尺寸针孔的情况下拿起一个物体。使用Vicon运动分析系统记录并重建三维运动学数据。测量的运动学参数包括运动总时间、最大速度、达到最大速度的时间、减速时间、最大抓握孔径、达到最大抓握孔径的时间以及达到最大抓握孔径后的时间。
限制视野会影响运动的运输和抓握部分。与全视野相比，两种受限视野下最大速度均降低（p = 0.008），最大抓握孔径均增大（p = 0.003）。仅11度视野的伸手和抓握部分的执行或在线控制时间也更长（分别为p = 0.005和p = 0.002）。
将视野缩小到11度（无周边视觉）会影响伸手和抓握动作部分的计划和执行。将视野限制在23度的中央视觉（存在一些周边线索）仅影响伸手和抓握动作部分的计划。因此，周边视觉线索对在线控制比对运动计划更重要。本研究结果对患有周边视力逐渐下降的眼部疾病患者具有重要的临床意义。
