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Low Contrast Acuity Measurement: Does it add value in the visual assessment of Down syndrome and Cerebral palsy populations?

Little, Julie-Anne, McCullough, Sara, McClelland, Julie F, Jackson, A. Jonathan and Saunders, Kathryn (2013) Low Contrast Acuity Measurement: Does it add value in the visual assessment of Down syndrome and Cerebral palsy populations? Investigative Ophthalmology & Visual Science, 54 (1). pp. 251-257. [Journal article]

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DOI: 10.1167/iovs.12-10506


Purpose: Children with Down syndrome (DS) and cerebral palsy (CP) often have reduced visual acuity (VA). This study assessed VA and low contrast acuity (LCA) with Lea symbols in DS and CP populations to explore whether LCA measures provide useful additional information about visual performance. VA and LCA were also measured from a large group of typically developing children. Methods: High contrast VA and LCA performance was measured monocularly using crowded Lea symbols on 45 children with CP (mean age 11.8+/-4years), 44 with DS (mean age 10.5+/-3years) and 211 controls (mean age 11.4+/-3years). Refractive status was confirmed with cycloplegic retinoscopy. Results: DS and CP groups had significantly lower acuities than controls at all contrasts (p<0.001). Mean (+/-SD) high contrast VA: DS=+0.39+/-0.2 logMAR; CP=+0.18+/-0.2 logMAR; controls=-0.04+/-0.1 logMAR. Mean 2.5% LCA: DS=+0.73+/-0.2 logMAR; CP=+0.50+/-0.2 logMAR; controls=+0.37+/-0.1 logMAR. For controls, the mean difference between VA and 2.5% LCA was 0.40 logMAR (95% limits of agreement +/-0.22 logMAR). Whilst there was a positive relation between VA and 2.5% LCA scores (linear regressions p<0.0001), considerable variation existed, with VA explaining only 36% of the variance in LCA performance for control data. Conclusion: VA and LCA performance was significantly poorer in DS and CP groups than in controls, and high contrast VA did not reliably predict low contrast performance. Therefore both high and low contrast acuity assessment are valuable to fully describe an individual's visual function, and this may be particularly relevant in DS and CP where patients may be unable to articulate visual difficulties. Age-specific reference data from a large sample of typically developing children across a broad age range are presented for clinicians using high and low contrast Lea symbols.

Item Type:Journal article
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:24394
Deposited By: Dr Julie-Anne Little
Deposited On:07 Jan 2013 10:02
Last Modified:22 Mar 2013 15:52

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