The aim of this study was to evaluate the visual function information obtained from multiple reading tests in a dry eye population.
In this case–control, single-center clinical research center– based study, 15 subjects with dry eye (mean age 65 years) and 10 normal subjects (mean age 40 years) were included. The Standardized Mini-Mental Examination was given to assure that subjects had normal cognitive function. Reading tests were both sentence based (Radner reading acuity test, reading contrast sensitivity test at a fixed print size, and menu-reading test) and paragraph based (Wilkins test and International Reading Speed Texts [IReST]). Wilkins and IReST tests were slightly modified to increase difficulty and visual stress. The main outcome measures were cognitive function, fatigue, dry eye symptoms, reading acuity, reading rate, and blink rate.
Results showed significantly lower rates in all reading tests in subjects with dry eye than in normal subjects; in the age-matched subgroup, only the menu and contrast sensitivity tests lost significance. Fatigue was significantly related to the IReST test, both at normal and critical print sizes. Reflex tearing was monitored and shown to significantly decrease the reading rate. IReST scores were considered the baseline, and the percent change from one test to IReST was also used to differentiate dry eye and normal subjects. The blink rate, symptoms, and demographics were not significantly correlated with reading tests.
Reading is a relevant end point that differentiates dry eye and normal subjects. This study evaluated a variety of reading tests for relevance as a measurable assessment of visual function in dry eye disease.