Meibomian Glands II
Meibomian Glands II
By Gary N. Foulks, MD, FACS
Because meibomian gland secretions play an integral role in preventing evaporation of the tear film, insufficient production of these lipids can result in accelerated tear film breakup and ocular surface damage, even when production of the aqueous component of the tear film remains normal. Since meibomian gland dysfunction often occurs concomitantly with aqueous-deficient dry eye disease, assessment and treatment of meibomian gland disease is often a necessary step in successful dry eye treatment.
Assessment of the Meibomian Glands
To evaluate patients for meibomian gland dysfunction, I start by examining the quality of the meibomian gland secretions. In a healthy eye, the meibum is a very thin, clear liquid that expresses easily when pressure is applied to the eyelid. When patients start to develop meibomian gland disease, however, the meibomian gland secretions become thicker and the glands change in appearance.
The first observable change in meibomian gland dysfunction is an increase in the viscosity of the meibum, which makes expressing the glands somewhat more difficult. As meibomian gland dysfunction progresses, the meibum also becomes increasingly opaque. At this stage, the meibum is still relatively thin — although not as thin as in the healthy eye — but it now appears cloudy rather than clear.
As meibomian gland dysfunction progresses, granule-like clumps begin to appear in the meibum, and eventually the meibum becomes so viscous that it is the consistency of paste. At this stage, one can still express the glands by pressing on the eyelids, but the secretions come out as a solid core rather than a liquid (Figure 1).
In addition to changes in the consistency and appearance of the meibum, the appearance of the glands themselves can indicate meibomian gland dysfunction. Therefore, I always look for signs of inflammation along the eyelid margin — either swelling of the lid margin or telangiectasia — when I suspect possible meibomian gland dysfunction.
Finally, I check for facial rosacea during the exam because meibomian gland disease is more common in patients with rosacea and sebaceous gland dysfunction. I also ask patients about systemic medications; medications such as retinoic acid (Accutane®) can obliterate meibomian glands and contribute to meibomian gland dysfunction.
Treatment of Meibomian Gland Dysfunction
When my assessment reveals that a patient has meibomian gland dysfunction, I treat the condition using a combination of simple therapies and drugs. In about 80% of patients, daily application of hot compresses to the eyelid followed by lid massage can help restore the normal consistency of the meibum, which in turn restores meibomian gland function.
When hot compresses and massage prove insufficient, I prescribe doxycycline or minocycline for at least 1 month. Also, if the patient has persistent inflammation in the lid margin, I sometimes use a topical corticosteroid or, occasionally, topical cyclosporine to bring this inflammation under control.
Whatever measures prove effective, normalizing the meibomian gland secretions allows patients to regain the protective benefit of these lipids. As a result, evaporation of the tear film is reduced, and dry eye signs and symptoms can improve significantly.
Gary N. Foulks, MD, FACS, is the Arthur and Virginia Keeney professor of ophthalmology, University of Louisville, Louisville, KY, and is editor-in-chief of The Ocular Surface.