Effects of meibomian gland dysfunction and aqueous deficiency on friction-related disease

Purpose: To evaluate the effects of meibomian gland dysfunction (MGD) and aqueous deficiency (AD) on friction-related disease (FRD). Methods: Cross-sectional comparative study. This study included 550 eyes (550 patients) with dry eye disease (DED). The DED subtype and dynamic tear-film parameters by automated assessments were investigated for the analysis of FRD (superior limbic keratoconjunctivitis, conjunctivochalasis, and lid wiper epitheliopathy). Results: Patients with FRD had a higher proportion of moderate-to-severe MGD and AD (p < 0.001 and p < 0.001, respectively). The dropout rate of the meibomian gland was higher (30.5 ± 31.8 and 14.1 ± 25.0%, p < 0.001), tear meniscus height (TMH) was lower (227.8 ± 60.4 and 241.7 ± 55.6 μm, p = 0.008), and he first non-invasive keratographic tear break-up time (NIKBUT-1) was shorter (5.9 ± 3.5 and 7.3 ± 3.7 s, p < 0.001) in patients with FRD than in those without FRD. In the logistic regression analysis with clinical manifestation, both moderate-to-severe MGD and AD were associated with FRD (odds ratios [OR] 12.27, 95% confidence interval [CI] 7.72–19.50, and 2.31, 95% CI 1.43–3.71], p < 0.001 and p < 0.001, respectively). The dropout rate was positively associated with FRD (OR 1.017, 95% CI 1.010–1.023, p < 0.001). TMH and NIKBUT-1 were negatively associated with FRD (OR 0.995, 95% CI 0.991–0.999, and 0.90, 95% CI 0.85–0.95, p = 0.039 and p < 0.001, respectively). Conclusions: This study showed that FRD was highly associated with MGD and meibomian gland dropout rate, suggesting that FRD may be mainly affected by lipid components. AD and TMH also had a good but relatively lower association with FRD, compared to MGD and meibomian gland dropout rate.