When the meibomian glands become blocked, inflammation of the eyelid margins (posterior blepharitis) occurs, along with a secondary impairment of ocular lubrication. Eyelid margin cleansing plus drainage or meibomian gland expression consists of special cleansing of the eyelid margins, removing debris and debris that block the glands' exit orifices. This is followed by mechanical expression of the meibomian glands in the eyelids to remove the solidified secretion that clogs them and allow them to produce normal oil again. This improves their function as vital components of ocular surface lubrication. Three cleansing and drainage sessions are performed, one every three weeks.