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Reach-to-precision grasp deficits in amblyopia: Effects of object contrast and low visibility

Grant, S. & Conway, M. L. (2015). Reach-to-precision grasp deficits in amblyopia: Effects of object contrast and low visibility. Vision Research, 114, pp. 100-110. doi: 10.1016/j.visres.2014.11.009


Adults with a history of unilateral amblyopia and abnormal binocularity have a range of visual deficits, with some of the 'higher' levels ones generalizing to their dominant (non-amblyopic) eye and linked to widespread binocular cortical network dysfunctions. Our interests are in how these problems also impact on their hand action control in real-world situations. We investigated whether eye-hand coordination deficits, known to exist in amblyopia when goal objects are presented under full-lighting and at high contrast, are exacerbated under low object-background contrast or in dim lighting/low visibility conditions. Hand movement parameters were recorded and quantified in 13 amblyopia and 13 control subjects while they reached-to-precision grasp objects using both eyes together or just their dominant or amblyopic/non-dominant eye alone under these 3 task conditions. Compared to controls, the amblyopia subjects spent significantly longer in preparing their movements, in the initial (planned) periods of their reach and grasp and in applying their grip, while making more reach and grasp errors under all 3 views and tasks. Deficits in planning and controlling the grasp were also selectively accentuated in the low contrast condition, but with no evidence of relatively worse performance under low environmental illumination. We suggest that the dysfunctions in amblyopia are associated with generalized difficulties in obtaining reliable visual evidence about the target's 3D properties during movement planning and in selecting and guiding the proper course of action, especially when segregating the object from background is more challenging.

Publication Type: Article
Additional Information: NOTICE: this is the author’s version of a work that was accepted for publication in Vision Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version has been subsequently published in Vision Research available here:
Publisher Keywords: Eye-hand coordination; Visuomotor control; Strabismus; Action planning
Subjects: R Medicine > RE Ophthalmology
Departments: School of Health & Psychological Sciences > Optometry & Visual Sciences
SWORD Depositor:
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