How Do Flanking Objects Affect Reaching and Grasping Behavior in Participants with Macular Disorders?

Pardhan, S., Gonzalez-Alvarez, C., Subramanian, A. & Chung, S.T.L. (2012). How Do Flanking Objects Affect Reaching and Grasping Behavior in Participants with Macular Disorders?. Investigative Ophthalmology and Visual Research, 53(10), pp. 6687-6694. doi: 10.1167/iovs.12-9821

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Abstract

Purpose: To investigate how objects (flankers) placed on either side of a target affect reaching and grasping behaviour in visually impaired (VI) subjects due to macular disorders compared to age matched normals. Methods: Subjects reached out to grasp a cylindrical target placed on its own and when it had two identical objects (flankers) placed either half or one target diameter away on each side of the target. A motion analysis system (Vicon 460) recorded and reconstructed the 3D hand and finger movements. Kinematic data for transport and grasping mechanisms were measured. Results: In subjects with VI, crowding effected the overall movement duration, time after maximum velocity and maximum grip aperture. Maximum effect was shown when the flankers were placed close to the target (high level crowding) with a decreased effect shown for flankers placed further away (medium level crowding). Compared to normals, subjects with VI generally took longer to initiate the hand movement and to complete the movement. Time after maximum velocity and time after maximum grip aperture were also longer in subjects with VI. No interaction effects were found for any of the indices for the different levels of crowding in the two visual groups. Conclusions: Reaching and grasping behaviour is compromised in subjects with VI due to macular disorders compared to normals. Crowding affected performance for both normal subjects and those with VI. Flankers placed half an object diameter away showed greater deterioration than those placed further away.

Item Type: Article
Uncontrolled Keywords: Science & Technology, Life Sciences & Biomedicine, Ophthalmology, OPHTHALMOLOGY, READING SPEED, LOW-VISION, PREHENSION MOVEMENTS, PERIPHERAL-VISION, SELECTIVE ATTENTION, SPATIAL INTERACTION, CONTOUR INTERACTION, OBSTACLE POSITION, VISUAL RESOLUTION, AMBLYOPIC VISION
Subjects: R Medicine > RE Ophthalmology
Divisions: School of Health Sciences > Department of Optometry & Visual Science
URI: http://openaccess.city.ac.uk/id/eprint/3510

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