Analysis of Visual Function in Subjects With Evaporative-Type Dry Eye Disease (DED)

Abstract

Purpose: : The alteration of visual function has been shown to greatly affect quality of life in patients with DED. The aim of this study was to analyze if these changes in visual function can be detected with the clinical tests more commonly used: best corrected visual acuity (BCVA) and contrast sensitivity (CS).

Methods: : A total of 22 DED subjects and 22 healthy age-matched subjects entered this study. In the DED group, the most symptomatic eye (MS-eye) and the least symptomatic eye (LS-eye) were compared with the same eye in the control group. BCVA was measured with the ETDRS chart. CS was measured with the CSV-1000 test and four spatial frequencies (3, 6, 12, 18 cpd) in addition to the area under the curve were analyzed. The Levene test was used for equality of variances and the Student t-test and Mann-Whitney U test were used for analysis of independent samples.

Results: : BCVA with ETDRS showed no differences between groups. However, CS was lower in DED patients, although significant differences were only found for 3 cpd in the LS-eye (3.95±1.86 vs 5.00±1.95; p=0.04). DED group presented a higher variability of CS for all special frequencies, being significant for 6 and 12 cpd in the MS-eye and for all frequencies except for 3 cpd in the LS-eye. CS in the DED group had an area under the curve significantly lower: 1) for the MS-eye in the interval area between 3 and 6 cpd (0.16±0.09 vs 0.21±0.04; p=0.018), and between 6 and 12 cpd (0.16±0.09 vs 0.21±0.05; p=0.046), and 2) for LS-eye in the interval area between 3 and 6 cpd (0.16±0.08 vs 0.21±0.05; p=0.012). Significant differences in CS variability for all interval areas under the curve were found in both eyes for the DED group compared to controls.

Conclusions: : CS, preferentially at low spatial frequencies, was lower in DED subjects than in healthy controls. These changes were greater in the eye chosen as the worst one by the patient (MS-eye). These results suggest that CS may be a reliable diagnostic evaluation end-point for DED and warrants further investigation.

Keywords: cornea: tears/tear film/dry eye • contrast sensitivity • quality of life