Meibomian Gland Dysfunction and Contact Lens Discomfort.

Meibomian glands are located in the eyelids and secrete meibum, which gives rise to the lipid layer of the tear film. Changes to these glands can lead to the development of meibomian gland dysfunction (MGD), which is associated with various ocular symptoms such as fatigue, dryness, burning sensation, and heavy sensation. The diagnosis of MGD thus relies on evaluation of ocular symptoms, meibum condition, and lid margin abnormalities. The recent development of noninvasive meibography and tear interferometry has provided important insight into meibomian gland structure and function, respectively. Wearers of contact lenses complain of ocular symptoms that are thought to be attributable to a variety of causes, such as a diminished aqueous or mucin layer of the tear film, changes in tear protein concentration, and altered meibomian gland structure or function. Many studies have examined the relation between contact lens wear and meibomian gland changes. Such studies have found that lens wear is associated with adverse changes in meibomian gland morphology and in the condition of the lid margin and meibum, suggesting that contact lenses negatively affect meibomian glands. Meibomian gland dysfunction-like changes in meibomian glands induced by contact lens wear may thus be responsible for at least some of the ocular symptoms in lens wearers.