By MILTON M. HOM, OD
Azusa, Calif.

Examination of the meibomian glands is essential for treating dry eyes. Studies have shown that meibomian gland dysfunction (MGD) occurs in around 40% of your patients. This article will review a technique called meibography you can perform to detect meibomian gland dysfunction.

How meibography works
Most of us rely on meibomian gland expression to determine the patency of the glands. A normally producing gland expresses meibum that is motor-oil like in consistency and puddles at the orifices. I like to see at least 75% of the glands producing this type of meibum.

Classification System for Meibomian Gland Dysfunction Based on Morphology

(Modified from: Caroline PJ. Kame RT. Meibomian gland dysfunction. In JA Silbert Anterior Segment Complications of Contact Lens Wear. Butterworth-Heinemann 1994)

GRADE 0 Normal Glands are uniform with a "piano key" appearance. No engorgement or stagnation of the gland structure is present.

GRADE 1 Minimal Some glands appear normal; others appear engorged and widened with early stagnation of meibum. The more prominent changes occur near the orifices.

GRADE 2 Mild Many glands are dilated and engorged with an obvious stagnation of meibum. There is increased irregularity of gland morphology especially near the lid margin. There are discrete collections of lipid.

GRADE 3 Moderate There may be enlargement of many glands secondary to stagnation of meibum. Multiple collections of lipid and microchalazia may be present subconjunctivally.

GRADE 4 Severe Numerous collections of lipid with increased numbers of microchalazia are present. Frank chalazion may be present.

One additional technique most helpful in gland evaluation is meibography by transilluminating the lids. Meibography shows the morphologic characteristics of the meibomian glands. The gland complexes are normally thin and relatively straight. In the past, meibography has been performed with transillumination and infrared silt lamp photography.

Some experts have concluded that stagnation of meibum causes an increase in pressure within the gland. The built-up pressure results in the morphological changes seen in meibomian gland dysfunction. Meibography can easily detect these changes.

You can perform a routine screening of the meibomian gland by using a simple transilluminator. The transilluminator tip can be used to evert the lower lid while providing transillumination. Under the magnification of the slit lamp, a detailed view of the meibomian gland can be made.

Figure 1 shows the transilluminated lid. The patient"s lower lid was gently everted over the transillumination light source. Direct visualization of the meibomian glands was made through the palpebral conjunctiva. The morphology is normal. The glands are dark areas of acini. The glands appear as dark structures within the lid. Figure 2 shows atrophic glands. The dark areas shown by the arrow are distorted, dilated and non-linear.

Some authors have come up with classification systems describing meibomian gland dysfunction related to morphology (see "Classification System for Meibomian Gland Dysfunction Based on Morphology" above).

FIG. 1:The slit lamp appearance of transillumination of the lower lid. Visualization of the meibomian glands was made through the palpebral conjunctiva. The morphology is normal.	FIG. 2: The dark areas shown by the arrow are distorted, dilated and non-linear. These atrophic glands do not have the "piano key" appearance of Figure 1.

Variations of gland morphology
Other variations of gland morphology come in hordeolum and chalazion. An internal hordeolum is a common infection of the meibomian gland. An external hordeolum involves the glands of Zeiss and Moll and is sometimes referred to as a stye. Chalazion is a granulomatous mass of cells within the lids. Microchalazia much smaller accumulations of cells. Microchalazia can be detected when transilluminating the lids under the magnification of the slit lamp. They appear as small areas within a dilated and distorted gland.

Classification System for Gland Dropout
GRADE 0	No dropout
GRADE 1	< 25% missing
GRADE 2	26-50% missing
GRADE 3	51-75% missing
GRADE 4	76% to 100% missing

Another classification system, which may be more useful, centers on the percentage of gland dropout (see "Classification System for Gland Dropout" above). Jerry R. Paugh of Southern California College of Optometry introduced me to this system. Basing the grading system on amount of dropout is much simpler and easier to use. I personally prefer this system to others.

A final word
Transillumination offers a quick and simple view of the meibomian glands. A distorted morphology explains why a gland is not producing meibum. The cause of contact lens intolerance related to dryness can be diagnosed more easily.

Dr. Hom (eyemage@mminternet.com) thanks Alan Sasai and Jerry Paugh for help in preparing this article.

Dry Eye Treatment Pearls
	Start with the most simple treatments and work your way up as needed, always keeping in mind that it may be necessary to discontinue lens wear for a period.
	Make sure that the patient is free of lid disease. If lid disease is present, initiate treatment and instruct the patient to reduce his contact lens wearing time, if he has not already done so. The patient should also frequently replace his contact lenses, either into daily or bi-weekly disposables.
	Start with the frequent use of non-preserved artificial tears. The tears will add much needed lubrication to an already compromised ocular surface. The non-preserved tears will decrease the risk of the lens retaining the sometimes toxic preservatives found in preserved tears. In the more difficult cases, the newer gel formulations are recommend for use at bedtime after lens wear. These supplements have a longer duration, but as they will periodically blur the patients" vision, qhs dosing is recommended.
	In some cases, the patient may need to have the puncta occluded if other therapies are at a maximum and the patient is still symptomatic.Occlusion works particularly well in patients with decreased tear volumes and reduced lacrimal lakes.
	Initially, patients can be somewhat intimidated and apprehensive about occlusion. Education of the patient is critical for a successful outcome. Start by inserting two temporary collagen plugs in the lower puncta of each eye. Some practitioners have discussed the benefits of plugging the superior puncta first, or occluding only one eye as a trial. We find that the lower puncta are very accessible and most comfortable for the patient. While occluding one eye may be the perfect theoretical approach, it sacrifices therapy for the fellow eye and may be more time consuming, as well as confusing to the patient. Schedule a follow-up visit with the patient should be scheduled within 10-14 days. It is important to remind the patient to continue to use tear supplementation in this period. Remember that with some insurance policies have a 10-day post-op period with occlusion; hence, reimbursement may be difficult if you see the patient within the post-op window and go on to insert silicon plugs.
	If occlusion is successful, the next step would be to permanently occlude the puncta with silicone plugs. It is important to educate the patient to continue using tear supplements and follow up with the patient in about 6-8 weeks. In some instances, permanent plugs become recurrently dislodged. If faced with this, then punctual cautery may be the answer.
	In some instances, it may be necessary to change the patient"s lens. A lower water content lens may be beneficial because these lenses will draw less water from the tear film and may perform much better than their high water counterparts. Some specialty lenses, such as Extreme H2O, may be beneficial even though they are considered a high water content lens. Some practitioners will advocate switching lenses first prior to punctual occlusion.
	Another area we have had success with treating moderate to severe dry eye contact lens wearers involves rehydration of the lenses. Usually about halfway through their daily wearing cycle, we ask our KCS patients to simply remove their lenses and place them in a case with fresh saline for about 30 minutes while concomitantly using non preserved artificial tears in their eyes. This period of rehydration often allows our more severe dry eye lens wearers to extend their wearing time significantly.
­ By MICHAEL R. BOLAND, OD, J. BRADLEY FLICKINGER, OD, ELIZABETH J. FLICKINGER, OD