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:

1. patients with history of previous ocular or intraocular surgery
2. ocular infection, non dry eye ocular inflammation, ocular allergy, autoimmune disease
3. history of intolerance or hypersensitivity to any component of the study medications
4. wearing contact lenses during the study period, presence of current punctal occlusion
5. pregnancy, lactating women, and children