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Determining the relative contribution of retinal disparity and blur cues to ocular accommodation in Down syndrome

Doyle, Lesley, Saunders, Kathryn J and Little, Julie-Anne (2016) Determining the relative contribution of retinal disparity and blur cues to ocular accommodation in Down syndrome. Scientific Reports, 7 (39860). [Journal article]

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URL: http://rdcu.be/oqhu

DOI: 10.1038/srep39860

Abstract

Individuals with Down syndrome (DS) often exhibit hypoaccommodation alongside accurate vergence. This study investigates the sensitivity of the two systems to retinal disparity and blur cues, establishing the relationship between the two in terms of accommodative-convergence to accommodation (AC/A) and convergence-accommodation to convergence (CA/C) ratios. An objective photorefraction system measured accommodation and vergence under binocular conditions and when retinal disparity and blur cues were removed. Participants were aged 6-16 years (DS n = 41, controls n = 76). Measures were obtained from 65.9% of participants with DS and 100% of controls. Accommodative and vergence responses were reduced with the removal of one or both cues in controls (p < 0.007). For participants with DS, removal of blur was less detrimental to accommodative responses than removal of disparity; accommodative responses being significantly better when all cues were available or when blur was removed in comparison to when proximity was the only available cue. AC/A ratios were larger and CA/C ratios smaller in participants with DS (p < 0.00001). This study demonstrates that retinal disparity is the main driver to both systems in DS and illustrates the diminished influence of retinal blur. High AC/A and low CA/C ratios in combination with disparity-driven responses suggest prioritisation of vergence over accurate accommodation.

Item Type:Journal article
Keywords:Down syndrome, accommodation, convergence
Faculties and Schools:Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Optometry and Vision Science
ID Code:37068
Deposited By: Dr Lesley Doyle
Deposited On:27 Feb 2017 09:45
Last Modified:17 Oct 2017 16:28

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