RESUMO
PURPOSE: To determine how Meibomian gland (MG) morphology affects MG function by means of gland expression with the effect of treatment. METHODS: Fifteen patients (aged 31.6 ± 13.1 years) from a dry eye clinic diagnosed with MG dysfunction had their 365 lower lid MGs visualised with a slit-lamp biomicroscopy. Using infrared meibography (Oculus K5m), MG length, width and tortuosity were objectively measured. Each MG was expressed and the meibum graded (0=clear fluid, 1=cloudy fluid, 2= particulate fluid, 3=inspissated, or 4 = no expression) to determine its functionality. Participants had functionality repeated each time following a sequence of a warm compress, debridement, and forcible expression after 5 min. RESULTS: Just over 10 % of complete length MGs gave clear expression, while about 5% did not express at all, with most expressed meibum being particulate in nature. In contrast, the majority of partial length glands gave inspissated expression (38 %), with 32 % not expressing at all. No MG of <10 % length expressed. MG gland length was correlated with gland expression (r=-0.507, p < 0.001) and MG tortuosity (r=-0.129, p < 0.001), but not MG width (r=-0.090, p = 0.167). Regardless of MG length, warm compress increased the quality of expression (p < 0.002). Debridement further improved expression in partial MGs (p = 0.003), but not forcible expression (p = 0.529). CONCLUSIONS: Length is the key functional morphology metric of lower lid MGs. Warm compress and massage increase the quality of expression in all, but the shortest glands and patients with partial length glands also benefit from debridement.