Visual and personal characteristics are associated with reading performance in normally sighted adults

Visual acuity (VA) only slightly explains variability in reading performance, whereas other visual and non-visual parameters have been reported to influence reading performance; however, in ophthalmologic and optometric clinical practice and research, where standardised reading tests are used, many of these parameters are often neglected. The purpose of this study was to give insight into how various visual and non-visual parameters are associated with reading performance in normally sighted subjects. In addition, reading speed over time was investigated to observe the influence of prolonged reading on standardised test performance.

Reading speed and the number of mistakes were assessed with long text paragraphs obtained from the International Reading Speed Texts (IReST) and short sentences obtained from the Radner Reading Charts in 71 persons (mean age: 55 years, range: 18 to 86 years) with a binocular distance VA of logMAR 0.20 or better. For each of the variables (distance and near VA, contrast sensitivity, stray light, age, sex, educational level, habitual reading hours and reading affinity), the association with reading performance was investigated with multivariate linear regression models. Reading performance over time was assessed with linear mixed models.

Contrast sensitivity was independently associated with reading speed (IReST paragraphs p = 0.002, Radner sentences p = 0.021). An interaction between age and education was found for both reading tests (p = 0.001), at an older age, reading speed was less influenced by educational level. Reading speed remained stable over time.

The present study shows that contrast sensitivity was independently associated with reading speed and an interaction effect was found between age and education. As these tests are easy to administer, it is recommended to assess them in clinical practice and scientific research. When using standardised tests in healthy subjects, prolonged reading proved not to be an issue for reading durations up to about 23 minutes.