The Effects of Blur and Eccentric Viewing on Adult Acuity for Pediatric Tests: Implications for Amblyopia Detection

Formankiewicz, Monika A. and Waugh, Sarah J. (2013) The Effects of Blur and Eccentric Viewing on Adult Acuity for Pediatric Tests: Implications for Amblyopia Detection. Investigative Ophthalmology & Visual Science, 54 (10). pp. 6934-6943. ISSN 1552-5783

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Purpose.: The detection of amblyopia in children relies on an accurate assessment of visual acuity. Visual deficits in anisometropic and strabismic amblyopia are different, but the influence of chart design, in particular position, and type of crowding features on visual acuity in the two types of amblyopia, is not clear. Certain aspects of amblyopic spatial vision are mimicked in healthy individuals by imposing increasing levels of blur and retinal eccentricity. We measured the effects of these conditions on visual acuity in healthy adults, with crowded and uncrowded vision tests. Methods.: Visual acuity was measured under conditions of blur (0–4 D) and eccentric viewing (0–5 degrees) using high-contrast optotypes derived from common children's acuity charts. Optotypes were presented in isolation, in commercially available crowded configurations, and in configurations with closer target-flanker separations than those currently available. Results.: Dioptric blur had similar degradative effects on crowded and isolated visual acuity (P > 0.05), whereas eccentric viewing resulted in a larger deterioration of visual acuity for crowded tests (E 2 of 0.86–1.06) than for isolated optotypes (E 2 of 1.57–1.72) (P < 0.05). Maximum crowding effects occurred for closer target-flanker separations than those currently used commercially. Conclusions.: In so far as blur and eccentric viewing mimic spatial acuity deficits in amblyopia, the results suggest that crowded tests might be of limited value in the detection of anisometropic amblyopia, but should be valuable in the detection of strabismic amblyopia. Crowding effects would be greater if flanking features were placed closer to the target than they currently are in commercially available charts.

Item Type: Journal Article
Keywords: blur
Faculty: ARCHIVED Faculty of Science & Technology (until September 2018)
Depositing User: Repository Admin
Date Deposited: 10 Mar 2015 12:27
Last Modified: 09 Sep 2021 19:02

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