June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
The effects of central and peripheral visual losses on reaching and grasping
Author Affiliations & Notes
  • Aachal Kotecha
    NIHR BRC for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, United Kingdom
    Visual Neuroscience, UCL Institute of Ophthalmology, London, United Kingdom
  • Rachel Fahy
    Visual Neuroscience, UCL Institute of Ophthalmology, London, United Kingdom
  • Gary Rubin
    NIHR BRC for Ophthalmology, UCL Institute of Ophthalmology & Moorfields Eye Hospital, London, United Kingdom
    Visual Neuroscience, UCL Institute of Ophthalmology, London, United Kingdom
  • Footnotes
    Commercial Relationships Aachal Kotecha, None; Rachel Fahy, None; Gary Rubin, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 2186. doi:
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      Aachal Kotecha, Rachel Fahy, Gary Rubin; The effects of central and peripheral visual losses on reaching and grasping. Invest. Ophthalmol. Vis. Sci. 2013;54(15):2186.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: This study aims to evaluate the relative contributions of central and peripheral vision to prehension in visually impaired adults.

Methods: Reaching and grasping was quantified using motion detection cameras (ProReflex, Qualisys AB, Sweden). Subjects reached and grasped one of two cylindrical objects placed at 20cm or 40cm from the hand. Measures were repeated 8 times under each test condition and the median used in subsequent analysis. Indices of prehension planning [movement onset (MO ms); peak speed (V mm/s), time to peak speed (ttV ms)], execution [movement duration (MD ms); path deviation ratio (PD)] grasping [peak grip aperture (PGA, angle), grip application time (GAT, ms)] and control [deceleration time (DT ms)] were quantified. Analyses were performed using repeated measures ANOVA.

Results: The results of 9 control (C), 11 age related macular degeneration (AMD) and 12 glaucoma (G) patients during binocular viewing are presented. There were significant group differences in movement planning [MO: p < 0.01, V: p = 0.03, ttV: p < 0.01] and grasping [GAT:p < 0.01] with aspects of execution and online control approaching significance [MD: p = 0.06; PD, p = 0.1]. AMD and G patients had longer MO ('far,large' condition mean [standard error]: C = 274 [46] ms; G = 378 [87] ms; AMD = 439 [104] ms), ttV (C = 594 [79] ms; G = 719 [103] ms; AMD = 766 [100] ms) and GAT (C = 411 [74] ms; G = 544 [126] ms; AMD = 644 [163] ms); however AMD reaching speed V was slower, suggesting a deficiency in some aspects of movement planning (C = 1032 [122] mm/s; G = 918 [150] mm/s; AMD = 854 [94] mm/s). In contrast, glaucoma patients displayed longer DT (C = 510 [109] ms; G = 552 [79] ms; AMD = 528 [74] ms) , MD (C = 935 [113] ms; G = 1078 [192] ms; AMD = 1060 [156] ms) and higher PD (C = 1.14 [0.04]; G = 1.16 [0.05]; AMD = 1.12 [0.04]) suggesting difficulties with online control.

Conclusions: This preliminary analysis suggests that whilst glaucoma and AMD patients have deficits in reach to grasp movements compared with controls, they display distinct differences in movement planning and online control. Further work will explore how these relate to their specific visual deficiency.

Keywords: 584 low vision • 753 vision and action  
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