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Jpn J Ophthalmol. 2008 Jan-Feb;52(1):44-7. doi: 10.1007/s10384-007-0494-6. Epub 2008 Mar 28.

How normal eyes perform in reading low-contrast texts.

Author information

1
Department of Ophthalmology, Surugadai Nihon University Hospital, Tokyo, Japan. kfujita@med.nihon-u.ac.jp

Abstract

PURPOSE:

To assess the performance of normal eyes in reading low-contrast texts.

METHODS:

We selected 14 subjects aged 20 to 31 years (mean, 23 +/- 3 years) with corrected visual acuity of 1.0 or better. The subjects were asked to read texts when the contrast between the characters and background was adjusted to 100%, 40%, 20%, and 10%. Using a computer-generated reading chart, reading acuity (RA), critical character size (CCS), and maximum reading speed (MRS) were assessed. The reading performance was compared at various contrast levels.

RESULTS:

When the contrast between the characters and background was 100%, 40%, 20%, and 10%, the mean RA (logMAR) was -0.08 +/- 0.07, 0.03 +/- 0.09, 0.13 +/- 0.09, and 0.26 +/- 0.11, respectively; the mean CCS (logMAR) was respectively 0.10 +/- 0.09, 0.18 +/- 0.09, 0.29 +/- 0.14, and 0.41 +/- 0.10. The mean MRS (characters/min) was 379.2 +/- 41.9, 369.7 +/- 43.3, 369.2 +/- 60.2, and 343.7 +/- 67.0, respectively. In all subjects, a decrease in contrast was associated with an increase in RA and CCS, but the MRS was not affected.

CONCLUSIONS:

In normal eyes, even when reading low-contrast texts, increasing the character size makes it possible to maintain the same MRS as when reading high-contrast texts.

PMID:
18369699
DOI:
10.1007/s10384-007-0494-6
[Indexed for MEDLINE]

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