AIM:To investigate the prevalence of demodex folliculorum in eyelashes of elderly patients with Meibomian gland dysfunction(MGD)and to find the correlation between the presence of demodex folliculorum and MGD.

METHODS: The study involved elderly patients(age≥40)who visited Department of Ophthalmology in Fujian Provincial Hospital for the Elderly between September 2017 and March 2018. Patients were divided into MGD group(137 patients 137 eyes)and non-MGD group(96 patients 96 eyes). The patients underwent eyelid examinations by slit lamp, lipid secretion of the Meibomian gland, fluorescein corneal staining(FL), tear film breakup time(BUT). At the same time underwent epilation of eyelashes, and the number of Demodex was counted. The positive rate of demodex was compared between the two groups, the relation of number of demodex with eyelid margin score, lipid secretion of the meibomian gland, FL score and BUT were evaluated.

RESULTS: The positive rate of demodex in MGD group was 89.1%, significantly higher than that of group non-MGD 74.0%(P<0.05). The number of demodex showed significant positive correlations with the eyelid margin(r=0.89, P<0.05), lipid secretion of the meibomian gland(r=0.67, P<0.05), FL(r=0.35, P<0.05)and BUT(r=-0.37, P<0.05). The mild infection rate of demodex mites in non-MGD(60.6%)was higher than MGD(37.7%, P<0.05).

CONCLUSION: There is a strong correlation between ocular moderate or severe demodex mites infection and MGD, suggesting that demodex folliculorum may play a pathogenic role in elderly patients with MGD.