Meibum Does not Flow to Tear Film

In some patients, meibum may be produced but, for a variety of reasons, it does not flow onto the tear film, resulting in evaporative dry eye.

Blockage may be due to stagnant meibum, thick or hardened meibum, fibrotic tissue that constricts the glands anywhere along their length, partial atrophy or drop out, infections, or inflammation.

Reference

The International Workshop on Meibomian Gland Dysfunction: report of the Subcommittee on Anatomy, Physiology, and Pathophysiology of the meibomian gland
Knop E, Knop N, Millar T, Obata H, Sullivan DA.
Investigative Ophthalmology and Visual Science
2011 Mar 30;52(4):1938-78. doi: 10.1167/iovs.10-6997c. Print 2011 Mar. PMID:21450915
View the full report