18 research outputs found

    Enhanced text spacing improves reading performance in individuals with macular disease

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    The search by many investigators for a solution to the reading problems encountered by individuals with no central vision has been long and, to date, not very fruitful. Most textual manipulations, including font size, have led to only modest gains in reading speed. Previous work on spatial integrative properties of peripheral retina suggests that 'visual crowding' may be a major factor contributing to inefficient reading. Crowding refers to the fact that juxtaposed targets viewed eccentrically may be difficult to identify. The purpose of this study was to assess the combined effects of line spacing and word spacing on the ability of individuals with age-related macular degeneration (ARMD) to read short passages of text that were printed with either high (87.5%) or low contrast (17.5%) letters. Low contrast text was used to avoid potential ceiling effects and to mimic a possible reduction in letter contrast with light scatter from media opacities. For both low and high contrast text, the fastest reading speeds we measured were for passages of text with double line and double word spacing. In comparison with standard single spacing, double word/line spacing increased reading speed by approximately 26% with high contrast text (p < 0.001), and by 46% with low contrast text (p < 0.001). In addition, double line/word spacing more than halved the number of reading errors obtained with single spaced text. We compare our results with previous reading studies on ARMD patients, and conclude that crowding is detrimental to reading and that its effects can be reduced with enhanced text spacing. Spacing is particularly important when the contrast of the text is reduced, as may occur with intraocular light scatter or poor viewing conditions. We recommend that macular disease patients should employ double line spacing and double-character word spacing to maximize their reading efficiency. © 2013 Blackmore-Wright et al

    Normative Reference Ranges for Binocular Summation as a Function of Age for Low Contrast Letter Charts

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    PURPOSE: Binocular summation (BiS), defined as the superiority of binocular over monocular viewing on visual threshold tasks, is most-often studied in laboratory settings. Few studies have evaluated BiS with readily-available clinical tools. Low contrast acuity (LCA) charts are increasingly popular in clinical research, yet their utility in detecting BiS has not been evaluated. METHODS: 129 normal subjects aged 3–85 years were prospectively enrolled, and underwent monocular and binocular testing using 2.5% and 1.25% Sloan LCA charts and Pelli-Robson (PR) contrast sensitivity (CS) charts at an academic institution. Subjects also underwent similar testing with Early Treatment Diabetic Retinopathy Study (ETDRSVA) charts. BiS was calculated as the difference between the better eye and binocular scores. RESULTS: Monocular and binocular scores decreased with increasing age for all metrics. The mean(±SD) BiS scores for 2.5% and 1.25% Sloan LCA were 6±4.5 and 3±5 letters, respectively. BiS score was 4.5±7 letters for PR charts and 2±3 letters for ETDRS VA. There was a significant effect of age on BiS for the low contrast metrics (p≤0.001 for all), but not for high contrast ETDRS VA. Linear regression revealed significant associations between increased interocular difference (IOD) in acuity and decreased BiS for all tests, and associations between increasing age and decreased BiS for the LCA tests. CONCLUSION: Of the clinical tests evaluated, 2.5% and 1.25% Sloan LCA charts most readily demonstrated BiS in young normal subjects. BiS declined with increasing age and increased IOD. Median values presented in this study may be useful for future clinical studies utilizing LCA
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