May 2003
Volume 44, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2003
Relation of Reading Performance to Visual Acuity and Perceived Reading Ability in Low Vision
Author Affiliations & Notes
  • R.W. Massof
    Ophthalmology, Johns Hopkins Univ Sch of Med, Baltimore, MD, United States
  • Footnotes
    Commercial Relationships  R.W. Massof, None.
  • Footnotes
    Support  NIH grant EY-12045
Investigative Ophthalmology & Visual Science May 2003, Vol.44, 1284. doi:
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      R.W. Massof; Relation of Reading Performance to Visual Acuity and Perceived Reading Ability in Low Vision . Invest. Ophthalmol. Vis. Sci. 2003;44(13):1284.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Abstract: : Purpose: To determine the relationship of reading speed vs. print size function parameters to visual acuity and to perceived reading ability. Methods: Reading speed vs. print size was measured on 50 low vision patients using MNRead at a distance of 40 cm with the patient's habitual correction and binocular viewing. Presenting binocular visual acuity was measured using the rear-illuminated ETDRS visual acuity chart with the patient's habitual correction. Perceived reading ability was estimated with a questionnaire for which patients rated the difficulty of performing specific reading tasks using a 4-category ordinal response scale. Results: Each set of reading speed vs. print size data was fit with the function R=Rmax*(1-exp{-2.3(P-P0)/(Pc-P 0)}), where R is the reading rate in words per minute, Rmax is the maximum reading rate, P is the print size in MAR, P0 is the threshold print size, and Pc is the critical print size (i.e., the print size that yields a reading rate 90% of Rmax). Perceived reading ability on an interval scale was estimated from difficulty ratings of reading tasks using Rasch analysis. Log MAR acuity ranged from 0 to 1.2; Rmax ranged from 19 to 265 words/min.; P0 ranged from 0 to 1.2 log MAR; and Pc ranged from 0.45 to 1.7 log MAR. There was a strong correlation between log P0 and log Pc (r = 0.77), log P0 and log MAR acuity (r = 0.59), and log Pc and log MAR acuity (r = 0.66). The linear regression between log MAR acuity and log P0 had a slope of 1 and an intercept of 0, whereas the linear regression between log MAR acuity and log Pc had a slope of 1 and an intercept of 0.47. The correlations between Rmax and log MAR visual acuity, log P0, and log Pc were weak (0.16, -0.25, and 0.18, respectively). Perceived reading ability was moderately correlated with Rmax, log P0, and log Pc (0.48, -0.46, and -0.41, respectively). Conclusions: Maximum reading rate is nearly independent of visual acuity, whereas reading threshold and critical print size are strongly associated with acuity. Critical print size is 3 times the reading threshold. Although maximum reading rate is not correlated with threshold or critical print size, perceived reading ability is associated with all three parameters.

Keywords: reading • low vision • visual acuity 
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