Table 11.

Assessment of Meibomian Gland Function

Based on Meibomian Gland Expression

Grades and comments

Methods: A plus Ba or Bb

A. Meibum quality: LL or UL, central 8 glands

0 = clear fluid

1 = cloudy fluid

2 = cloudy particulate fluid

3 = inspissated, like toothpaste.

Ba. Meibum expressibility: LL or UL, central 8 glands

0 = all glands expressible

1 = 3–4 glands expressible

2 = 1–2 glands expressible

3 = no glands expressible

Bb. Meibum expressibility: LL nasal or central eight glands

The MGYLS score is the number of Meibomian Glands of eight, Yielding Liquid Secretion.

Assessment by gland expression

≤20 years: A score of greater than 1 for quality or expressibility (A; B) is abnormal.

>20 years: A score of 1 for either quality or expressibility is acceptable as normal; a score of 1 for both, or of >1 for either, is abnormal.

For research and some clinical trial purposes, the utility of this approach would be enhanced by generating a composite score derived from the expression of the LL, UL nasal and central zones.

Based on Meibomian Gland Dropout

Meibography: The technique of meibography offers an excellent opportunity to refine the quantification of gland loss by digitizing the images. It should be noted that estimates of 'gland loss' are based on an assumption of the original size of ea ch gland. Therefore estimates of residual gland area will be more accurate, although relevant to a particular individual. There is a need for detailed age/sex stratified information about gland area.

A precise description of any technique proposed must be given. For example, if the term 'partial gland loss' is used, this must be defined. An estimate of loss is based on the presumed, intact length of each gland. Training would be enhanced by the use of videos showing both the performance of the technique of method of scoring in use.

Either contact or noncontact meibography can be used.

Method C: LL 15 glands: A partial gland is one that is incomplete and present in clumps or clusters.

1 = no partial glands (PGs)

2 = <25% PGs

3 = 25%–75% PGs

4 = >75% PGs

An aggregate score from the combined LL/UL would expand the scale

Method D: (nasal half, lower eyelid)*

0 = no dropout

1 = ≤25%

2 = ≤50%

3 = ≤75%

4 = ≤100%

Based on Meibography

≤20 years. Method C. Normal is 0

>20 years. Method C. 1 = ≤25% is acceptable as normal; >1 is abnormal

Diagnosis of MGD-related disease, including dry eye:

In the general clinic. See Table 8

In a specialized clinic. See Table 8

MGD Criteria for Specific Purposes Clinical practice: See diagnostic criteria above Recruitment for clinical trials Therapy of ADDE. Accept a mild degree of MGD. Record the grade of MGD on the basis of gland expression and with or without baseline dropout. Use data for stratification in data analysis. Therapy for MGD. Recruit patients with moderate to marked MGD. Establish criteria for irreversible disease' and ensure that the each individual in the sample has sufficient reversible MGD to make treatment viable MGD as a potential adverse event In studies that aim to detect and monitor meibomian gland changes as an adverse event the population should be young adults (<40 years) to minimize baseline MGD scores and maximize detectability of change. Natural History of MGD Studies of the natural history of 1° and 2° MGD are required, in patients on or off treatment. There are no specific recruitment criteria.

^*de Paiva et al.¹⁰⁶ have also devised a composite score including lids signs and expressibility, with a scale range of 0–11.