The relation between Demodex colonization and manifestations of meibomian-gland dysfunction

Background and aim Meibomian-gland dysfunction (MGD) is a very common disease we face every day in the clinic. It is the essential cause of evaporative dry eye. It is a chronic, diffuse disorder of the meibomian glands, distinguished by terminal-duct obstruction and/or qualitative/quantitative variations in glandular secretion. It may result in alteration of the tear film, manifestations of eye irritation, clinically evident inflammation, and also ocular-surface disease (OSD). The aim of the study was to relate Demodex colonization to MGD. Patients and methods This study included 76 eyes divided into two groups, group A (patients’ group) included 38 eyes with MGD, group B (control group) included 38 eyes with normal lid margin. Both groups were subjected to history taking, MGD evaluation by MGD grading, fluorescein breakup time, OSD index, Schirmer-1 test, and lash sampling. The lashes sampled were examined for Demodex colonization by light microscopy. Results There was a statistically significant difference in Demodex colonization between the patients’ group 16 (42.1%) eyes and the control group four (10.5%)eyes. We noticed predominance of female sex in the MGD patients’ group (84.2%). There was a statistically significant difference between the two groups regarding fluorescein breakup time, OSD index, and Schirmer-1 test with P value less than 0.001. Conclusion Demodex colonization is incriminated as an important cause of MGD and OSD. Our study suggests that treating Demodex is crucial in MGD patients.