What is Meibomian Gland Dysfunction?


Meibomian Gland Dysfunction (MGD) is a chronic, diffuse abnormality of the meibomian glands most often associated with blepharitis*, meibomitis**, ocular rosacea***, environmental allergies, autoimmune conditions, and/or demodex**** (see definitions below). Meibomian glands are oil producing glands in the eyelid margins of both your upper and lower eyelids. These glands produce the oil which comprises the outermost layer of your tears. This oily layer protects your tears from evaporating. When these oils are reduced, the evaporation of your tears from the surface of your eyes is increased and your eyes become drier much more quickly, especially when you are reading a computer screen, cell phone, tablet, document, watching T.V., driving, etc.

Since MGD often results from blepharitis, meibomitis, ocular rosacea, and/or demodex, it is very important to determine whether or not you have any of these conditions. It is also important to know that, if not properly diagnosed and treated, these conditions are chronic and progressive. These conditions adversely affect your eyes causing irreparable damage in two very important ways: first, by causing irritation and inflammation of your eyes and eyelids leading to damage of your tear producing glands, and second, by causing blockage, structural damage and loss of your oil secreting meibomian glands.

Blepharitis, meibomitis and ocular rosacea are very closely related and have a lot of overlap with regard to their causes, symptoms and treatment. They all cause damage to your meibomian glands secondary to the accumulation of debris and a biofilm***** on your eyelids that blocks the openings of the meibomian glands thereby obstructing oil flow, along with a thickening of the glands’ contents. If left untreated, meibomian gland blockage, and the thickening of the glands’ contents, cause in increased pressure resulting in structural damage and eventual loss, or death, of your glands. Once lost, Meibomian glands do not have the ability to regenerate.


Terms Defined

Blepharitis is a condition where there is inflammation of the eyelids around the area of the eyelashes and the meibomian glands. You can have a seborrheic component (often with "dandruff" in your eyelashes) and/or a bacterial (staphylococcal) component sometimes causing styes or chalazia.

Meibomitis refers to the inflammation and dysfunction of the meibomian glands in the eyelid margins. When the meibomian glands are healthy, the oil they produce has the consistency of olive oil, which is the desired quality. When the glands are inflamed the oils they produce are thicker, like toothpaste, which is of poor quality and are less effective at lubricating the eyes. Additionally, when the meibomian glands are inflamed and the oily secretions thicken, the glands become clogged. When the glands become clogged, they become damaged and often close off ("drop out") and die, ceasing to produce any oil at all. If this condition is allowed to progress, you will ultimately have significant problems with dry, red, irritated and inflamed eyes. This increases your risk for recurrent infections involving your eyes and eyelids, scarring of the surface of your eyes, decreased vision and significant discomfort.

***Ocular Rosacea:
Ocular rosacea is characterized by inflammation of the eyelids. It is often the first sign of rosacea of the face (which involves the nose, cheeks, forehead and chin). People with rosacea tend to blush or flush easily. People with rosacea also have a much higher incidence of Demodex infestation.

Demodex mites are little bugs that can infest your eyelashes, eyelash follicles and eyebrows. These mites are nocturnal, coming out of your eyelash follicles at night to eat, mate and lay their eggs. Their life cycle is typically 2 to 3 weeks. If your eyelashes are infested with Demodex you may experience redness or irritation of your eyelids, dandruff in your eyelashes, and occasional itching, while some people experience no symptoms at all. Demodex infestation causes damage to your meibomian glands, making it important to quickly diagnose and treat the infestation.

A biofilm is a slimy, sticky film of bacteria that coats the surface of the eyelids. A biofilm is composed of a well-hydrated matrix of bacteria and their glycocalyx, a sugary coating that allows cells to adhere to and communicate with each other. The eyelid margin—with its moisture, nutrients and warmth—is the perfect environment to cultivate a thriving bacterial biofilm.