Analysis of Factors Associated with Anterior Location of Marx's Line.

PURPOSE: The study aimed to investigate the factors associated with anterior location of Marx's line in ocular surface and living habits, especially in tear film.

MATERIALS AND METHODS: This cross-sectional study enlisted 483 participants with meibomian gland dysfunction, who were divided into two groups: 160 participants with mild anterior location of Marx's line and 323 participants with moderate-to-severe anterior location. Participants completed a survey of demographic characteristics (sex, age, length of visual terminal use, sleep duration, skin property), and the Ocular Surface Disease Index and Standard Patient Evaluation of Eye Dryness questionnaires. They also underwent slit-lamp examinations of the lids, and measurements of non-invasive tear break up time, tear meniscus height, fluorescein tear break up time, lipid layer thickness, partial blink rate, lid wiper epitheliopathy, and meibomian gland dropout.

RESULTS: The tear meniscus height (mild:0.21(0.18-0.25), moderate-to-severe:0.19(0.16-0.23), p  = 0.004), fluorescein tear break up time(mild:3(2-4),moderate to severe:2(1-3), p  = 0.000), max LLT(mild:87(62-100), moderate-to-severe:99(69-100), p  = 0.04), average LLT(mild:64.5(47.5-96.75), moderate-to-severe:74(53-100), p  = 0.012), min LLT(mild:52(38-75), moderate-to-severe:59(41-85), p  = 0.029) differed significantly between mild and moderate-to-severe anterior location of Marx's line, and associated to the anterior location of Marx's line(r=-0.134, p  = 0.03; r=-0.194, p  = 0.000; r  = 0.093, p  = 0.041; r  = 0.119, p  = 0.009; r  = 0.105, p  = 0.022) However, no statistical significance was observed in the OSDI, SPEED, partial blink rate, non-invasive tear breakup time, lipid layer thickness, meibomian gland dropout and lid wiper epitheliopathy( p  > 0.05). Meanwhile, in the demographic characteristics, statistically significant correlations were associated with skin property( r  = 0.154, p  = 0.001) and sleep duration(r=-0.124, p  = 0.006), but not with age, sex, and the length of visual terminal use ( p  > 0.05).

CONCLUSIONS: Lower TMH and shorter TBUT positively correlated with anterior location of the Marx's line, and were risk factors. Meanwhile, participants with oily skin and shorter sleep duration were more likely to exhibit anterior location of Marx's line.