Comparing the Ocular Surface Mucin levels in Visual Display Terminal Users with and without DED

22 May, 23

Introduction

The use of visual display terminals (VDT) has increased in recent years, and the increased use of VDT has been linked to increased risk of dry eye disease (DED). Nevertheless, the exact mechanism which leads to DED in VDT users has not been clearly understood until now. Studies have also established the role of ocular mucins in the pathogenesis of DED.

Aim

To compare the mRNA levels of MUC1, MUC4, MUC16, MUC20, and MUC5AC in conjunctival impression cytology (CIC) samples of VDT users having DED vs. those without DED
To explore the link between mucin expression levels and the frequency of ocular symptoms, and various parameters of DED.

Profile of the Study Participants

Individuals exposed to VDTs for more than six months (at least 5 days per week and 6 h per day) (79 eyes)
Patients were categorized as follows:

VDT users with DED (53 eyes)

VDT users without DED (control group; 26 eyes)
DED Patients were further categorized into symptomatic and asymptomatic DED group.

Methods

Study Design

A cross-sectional study

Assessments

The subjective symptoms of DED were assessed using the 12-item ocular surface disease index (OSDI) questionnaire.
Other assessments included:

Conjunctival staining
Tear breakup time (TBUT)

Tear meniscus height (TMH)
Quantitative real-time PCR to determine relative mRNA expression

Results

Compared to the control group, individuals in the DED group had higher OSDI, corneal fluorescein staining (CFS), and lissamine green (LG) scores (all P <0.05), but shorter TBUT and TMH (both P <0.05).
Individuals in the DED group had lower levels of MUC1, MUC16, and MUC20, compared to the controls. Levels of MUC4 and MUC5AC did not differ significantly between the DED and control groups.
Expression of MUC1, MUC16, and MUC20 on foreign body sensation was lower in symptomatic vs. asymptomatic DED group.
The symptomatic group had decreased expression of MUC20 for painful or sore eyes vs. asymptomatic group.
The expression of five mucins and the frequencies of other ocular symptoms such as sensitivity to light and poor vision did not differ much in the symptomatic and asymptomatic groups.
The levels of MUC1, MUC16 and MUC20 correlated negatively with OSDI (r=-0.297, P=0.014; r=-0.323, P=0.007; r=-0.347, P=0.003, respectively), and positively with TBUT (r=0.334, P=0.005; r=0.337, P=0.005; r=0.309, P=0.010, respectively). The levels of MUC16 and MUC20 correlated positively with TMH (r=0.254, P=0.036; r=0.247, P=0.040, respectively).
The levels of MUC1, MUC16 and MUC20 did not correlate significantly with any other DED parameters.

Conclusions

VDT users with DED had reduced expression of conjunctival MUC1, MUC16, and MUC20 compared to those without DED.

VDT users with increased frequency of ocular discomfort and poor tear film stability have significantly reduced conjunctival MAMs levels.

Understanding mucin alterations in with VDT-associated DED may provide valuable insights on its progression mechanisms and to develop effective treatment strategies.

BMC Ophthalmol. 2023;23:189.DOI: 10.1186/s12886-023-02931-3.