Lower tear meniscus in computer reading task with and without soft contact lens

Abstract

Dry eye is the major contributor to computer vision syndrome. The reductions in the blink rate and amplitude have been considered as the possible mechanisms leading to this condition. The purpose of this study is to evaluate the changes in the lower tear meniscus heights and areas in the computer reading task, in dry eye subjects, with and without soft contact lenses. In this quasi-experimental study , 39 subjects (with mean age of 21.2 ± 2.4 years), with dry eye, were enrolled. The lower tear meniscus height and area (TMH, TMA) of the right eye was captured by Spectral Optical Coherence Tomography before and after 45 minutes of reading task behind desktop 17” Cathode Ray Tube monitors. The same procedure was performed after the insertion of the hydrogel soft contact lenses with 58% water content. The results of TMHs, TMAs were analyzed with a repeated measures analysis of variance (ANOVA) with two within-subject factors. : The mean ± standard error of TMH and TMA pre and post computer tasks were 283.6± 25.4 µm, 0.029±0.005 mm2, 297.6±20.7 µm , 0.036 ± 0.005 mm2 respectively. After contact lens insertion, the mean TMH and TMA pre and post computer task were 231.6 ± 10.6 µm, 0.020±0.0019 mm2, 213.0±9.0 µm, 0.018 ± 0.0011 mm2, respectively. Repeated measures analysis of variance showed that the changes in TMH (P=0.86) and TMA (P=0.37) after computer task, were not statistically significant, while the insertion of the soft contact lens had reduced the TMH and TMA significantly (P<0.001 for both). After 45 minutes of reading task behind desktop monitors, the tear volume has not changed, with and without high water SCLs. A reduction in tear volume might be expected with longer duration of computer task or at late hours of the day. The creation of a more stable tear film should be considered in the management strategies for shorter duration of work behind desktop monitors.