Evaluation of Reading Speed and Contrast Sensitivity in Dry Eye Disease

Abstract

Visual disturbance is a common symptom reported by patients with dry eye disease (DED). The purpose of this study was to evaluate visual performance, including reading speed and contrast sensitivity, in control and DED subjects. Fifty-two DED patients (mild, n = 17; moderate, n = 22; severe, n = 13; based on corneal staining and the Ocular Surface Disease Index ≥ 20) and 20 control subjects (Ocular Surface Disease Index <13, no corneal staining) took part in this study. The age ranges for the control and DED patients were 18 to 45 years and 19 to 84 years, respectively. Contrast sensitivity was measured using the Holladay Automated Contrast Sensitivity System, and reading speed was determined using the Wilkins Rate of Reading Test. Analysis of covariance was conducted to compare clinical characteristics among subject groups while adjusting for age, sex, and study site. Partial correlation coefficients from linear regression were used to measure the linear relationship between contrast sensitivity and reading speed with DED parameters. The log of the minimum angle of resolution visual acuities and contrast sensitivity were not significantly different across subject groups. The DED patients (134.9 ± 4.95 words per minute) exhibited slower reading speeds than the control subjects (158.3 ± 8.40 words per minute, p = 0.046). As DED severity increased, the reading speed decreased (141.0 ± 7.96 words per minute, 136.8 ± 7.15 words per minute, and 127.0 ± 9.63 words per minute in mild, moderate, and severe groups, respectively). Reading rate was found to correlate weakly with corneal staining based on a partial correlation coefficient (-0.345, p < 0.001) but not with other DED parameters. The reading rate was lower in DED subjects than that in control subjects. As the DED severity increased, the reading rate decreased. This finding is consistent with patient-reported symptoms and provides direct evidence for the impact of DED on reading performance. These findings suggest that reading speed may be used to monitor treatment benefit in DED.