As a non-invasive ocular imaging tool, in vivo confocal microscopy(IVCM)provides micro-structural information of cornea, conjunctiva and meibomian glands at the cellular level to display their microscopic structure features. IVCM supplies a unique advantage to clinical applications and research in ocular surface. Recently, application of IVCM has progressively extended to the research area on meibomian gland dysfunction(MGD)and on other diseases about meibomian gland. Thus, this paper aims to summarize the current knowledge about the role of IVCM in the assessment of meibomian glands.