In this study, investigator aim to evaluate the changes of tear-film lipid layer thickness and ocular aberration after treatment of meibomian gland dysfunction. In case of stage 3 or 4 meibomian gland dysfunction, participants will be treated using conventional treatment modalities. Before treatment and after 1 and 2 months of treatment, a variety of ophthalmic examination, tear-film lipid layer thickness, and ocular aberration are going to measured and compared.
Inclusion Criteria:
1. age over 19 years old, with moderate to severe Meibomian gland dysfunction.
Exclusion Criteria: