Decreased Mucin Expression May Explain Dry Eye in Frequent Screen Users

Decreased mucin expression in the conjunctival cells may be observed among video display terminal (VDT) users who report frequent ocular discomfort or have clinically diagnosed dry eye disease (DED), according a study published in BMC Ophthalmology.

Researchers recruited 79 participants who used VDTs at least 6 hours per day, 5 days per week, for more than 6 months for the cross-sectional study. Participants underwent Ocular Surface Disease Index (OSDI), tear breakup time (TBUT), corneal fluorescein staining (CFS), and tear meniscus height (TMH) assessments. Conjunctival impression cytology determined MUC1, MUC4, MUC16, MUC20, and MUC5AC mRNA expression levels between individuals with (n=53; mean age, 23.66 years; 38 women) and without a clinical DED diagnosis (n=26; mean age, 22.27 years; 20 women).

Participants with DED demonstrated significantly higher OSDI (mean, 41.67 vs 19.10; P <.001) and CFS scores (mean, 1.00 vs 0.00; P =.002) and lower TBUT (mean, 3.00 vs 12.00 seconds; P <.001) and TMH (mean, 0.20 vs 0.24 mm; P =.011) values compared with control group participants.

Decreased mucin expression (MUC1, MUC16, and MUC20) was observed among patients with DED compared with control group individuals (all P <.001), but there were no differences in MUC4 (P =.748) and MUC5AC (P =.226) expression levels between groups.

There were significant associations between decreased mucin expression levels and DED symptoms, according to the report. Foreign body sensation was associated with decreased MUC1 (P =.043), MUC16 (P =.017), and MUC20 (P =.007) expression, blurred vision was associated with decreased MUC1 (P =.011), MUC16 (P =.023), and MUC20 (P =.009) expression, and pain or soreness was associated with lower MUC20 expression (P =.031) among symptomatic individuals compared with asymptomatic individuals.

MUC1 expression levels correlated with OSDI scores (r, -0.297; P =.014) and TBUT (r, 0.334; P =.005). MUC16 levels correlated with OSDI scores (r, -0.323; P =.007), TBUT (r, 0.337; P =.005), and TMH (r, 0.254, P =.036). MUC20 levels correlated with OSDI scores (r, -0.347; P =.003), TBUT (r, 0.309; P =.010), and TMH (r, 0.247; P =.040).

“Understanding mucin alterations associated with VDT-associated DED is crucial for elucidating its progression mechanisms and finding effective treatment strategies,” according to the study authors.

Study limitations include failure to assess conjunctival protein levels in conjunction with decreased mucin expression, a single center design, and the potential for volunteer bias.