Blog | Wednesday, June 18, 2014

QD: News Every Day--Heavy computer users, dry eye sufferers may share tear film abnormality

Office workers who spend long hours at computers, as well as those with an increased frequency of eye strain, had a low concentration of a mucin in their tears that was similar to patients with dry eye disease, a study found.

To determine the relationship between mucin 5AC (MUC5AC) concentrations in tears among those who used computers extensively and the frequency of ocular symptoms, researchers conducted an institutional, cross-sectional study of the eyes of 96 young and middle-aged Japanese office workers. MUC5AC helps clear the ocular surface of debris and also helps hold fluids to the ocular surface.

Participants completed questionnaires about their working hours and the frequency of ocular symptoms. Dry eye disease, defined by subjective symptoms, tear fluid abnormalities, and keratoconjunctival disorder, was diagnosed as definite or probable, or it was not present.

Results appeared online June 9 in JAMA Ophthalmology.

Mean duration of VDT use was 8.2 (1.9) hours per day. The mean MUC5AC concentration was lower in the tears of heavy computer users with definite dry eye than in those with no dry eye (P=0.02; Hodges-Lehmann estimator, −2.17; 95% CI, −4.67 to −0.30). The mean MUC5AC concentration in the group who worked more than 7 hours was 5.9 [SD, 6.1] ng/mg; 86 eyes), which was lower than that in the group working less than 5 hours: 9.6 [12.3] ng/mg; 38 eyes) (Steel test, P=0.049). The estimated difference was −1.65 (95% CI, −3.12 to 0.00). Furthermore, MUC5AC concentration was lower in participants with symptomatic eye strain than in asymptomatic individuals (P=0.001; estimated difference, −1.71; 95% CI, −2.86 to −0.63).

“Our data indicate that MUC5AC mRNA expression is not altered in VDT (video display terminal) users,” the authors wrote. “However, a previous study has shown that MUC5AC mRNA levels are significantly reduced in patients with moderate to severe DED (dry eye disease). Because most of the definite DED in the present study was mild, we hypothesize that the difference in DED severity between the 2 studies accounts for the discrepancy in MUC5AC mRNA expression.”

Editor's Note: QD: News Every Day will resume on Monday, June 30.