Table 9.

Staging the Severity of MGD and Individual Clinical Parameters

	Severity Level
	Level 0 Normal	Level 1 Subclinical	Level 2 Symptomatic Minimal	Level 3 Symptomatic Mild	Level 4 Symptomatic Moderate	Level 5 Symptomatic Severe
Symptom frequency and severity	No symptoms	Asymptomatic or occasional symptoms	Some of the time; precipitated by environmental factors	Half of the time; some limitation of activity	Most of the time; frequent limitation of activity	All of the time Severe/disabling/constant
OSDI grade range (0–100)	0	0–12	0–12	13–22	23–32	33–100
MGD Grade	Clear	Subclinical, nonobvious MGD; altered quality, only on expression; no gland loss	Minimally altered quality of expressed meibum from scattered glands; None to minor gland loss	Mildly altered meibum quality; occasional lid margin signs; mild gland loss	Moderately increased opacity and viscosity of meibum; plugging; increased marginal vascularity; loss of orifice definition; moderate gland loss	Marked, diffuse MGD; cicatricial or noncicatricial; multiple lid margin signs; lid deformity and marked lid margin hyperaemia; Severe gland loss
Quality of expressed meibum grade range 0–3, LL, 8 glands, Range (0–24)*	0	1–5	6–10	11–15	16–20	21–24
Treatment of MGD based on symptoms and gland status		+ General advice about MGD, the potential influence of diet, home and work environment	+ Hygienic measures, heat and massage	±Topical ATs	+Oral tetracycline derivatives	± Anti-inflammatories
		±Hygienic measures		± Emollient lubricant or liposomal spray
				± Topical azithromycin
				± Consider oral tetracycline derivatives

This table should be read in conjunction with Table 11, which provides a staging scheme for MGD-related ocular surface disease. Severity levels for each parameter are graded 1–5. A subclinical severity level has been introduced to accommodate asymptomatic MGD with normal lid margin features (nonobvious MGD) diagnosed only after gland expression. Note that this MGD scoring system does not provide a score for totally obstructed glands. Alternative systems for grading MGD exist and should be considered (see Appendices 5–7). Arita et al.³ graded meibomian dropout in the combined upper and lower lids, using noninvasive meibography, with a scale range of 0–6 (Table 3). de Paiva et al.¹⁰⁶ used a composite system combining dropout, lid signs and meibum expressibility, with a scale range of 0–11 (Table 3). Korb and Blackie⁵² record the number of glands in a zone of 8, which yield a liquid secretion after standardized expression (MGYLS score 0–8). General treatment concepts, summarized here, are adapted from the Report on Management and Therapy. Recommended treatments are additive. At each clinical assessment, lack of response to treatment at the previous level moves treatment to the next level. ±, the decision to use this treatment is based on clinical judgment; +, treatment is recommended at this level. LL, lower lid; OSDI, Ocular Surface Disease Index.

^*The increase in severity of MGD with increase in grade is denoted by a reduced quality of expressed meibum. Meibum quality (clarity and consistency) is assessed in eight glands of the central third of the lower lid on a 0–3 scale for each gland: 0 = clear; 1 = cloudy; 2 = cloudy with debris; 3 = thick, like toothpaste (total score range 0–24).⁷⁵