Gary N. Foulks

DOI:10.1167/iovs.10-6997a Investigative Ophthalmology & Visual Science, Special Issue 2011, Vol. 52, No. 4 Copyright 2011 The Association for Research in Vision and Ophthalmology, Inc. 1922 ドライアイ疾患の原因としては、マイボーム腺機能不全 (MGD)がおそらく最も多い。この疾患によって数百万人 もの健康と幸福が損なわれているにもかかわらず、MGD の定 義、分類、診断、治療について世界的なコンセンサスはない。 そうしたコンセンサスに達する目的で、非営利団体である Tear Film and Ocular Surface Society( TFOS; http://www. tearfilm.org)が International Workshop on Meibomian Gland Dysfunction(国際マイボーム腺機能不全ワークショップ、 www.tearfilm.org/mgdworkshop/index.html)を起ち上げた。こ のワークショップの目的は以下の通りである:

Recommended definition of MGD: Meibomian gland dysfunction (MGD) is a chronic, diffuse abnormality of the meibomian glands, commonly characterized by terminal duct obstruction and/or qualitative/quantitative changes in the glandular secretion. This may result in alteration of the tear film, symptoms of eye irritation, clinically apparent inflammation, and ocular surface disease. Previous definitions and criteria of MGD: There is no firmly established definition of MGD published in the literature. Most researchers have used a criterion-based approach to describe the condition, with combinations of objective findings and measurements. Anatomic changes of the lid margin, expressibility of meibomian lipids, gland dropout by meibography, evaporimetry, and meibometry are most commonly used.

PURPOSE: To evaluate in a general clinic-based cohort of patients with dry eye disease (DED) the distribution of patients with aqueous-deficient or evaporative subtype of DED. METHODS: Schirmer tests and meibomian gland dysfunction (MGD) (Foulks-Bron scoring) were evaluated in both eyes of 299 normal subjects and DED patients (218 women and 81 men) across 10 sites in the European Union and the United States. Using the more severe measurement of the 2 eyes, subjects were considered to have pure aqueous-deficient dry eye (ADDE) with Schirmer values of <7 mm and MGD grades of ≤5. Patients were classified as purely evaporative dry eye with MGD grades of >5 and Schirmer values of ≥7 mm. Subjects were placed into the mixed (hybrid) category if they exhibited both a low Schirmer value of <7 and evidence of MGD with a grade >5. RESULTS: Of the 224 subjects classified with DED using an objective, composite, disease severity scale, 159 were classified into 1 of 3 categories: 79 were classified with only MGD, whereas only 23 were classified as purely aqueous deficient, and 57 showed evidence of both MGD and aqueous deficiency. Overall, 86% of these qualified DED patients demonstrated signs of MGD. The remaining 65 patients showed evidence of DED through other clinical signs, without overt evidence of MGD or ADDE, possibly because of the inherent variability of these signs. CONCLUSIONS: The proportion of subjects exhibiting signs of evaporative dry eye resulting from MGD far outweighs that of subjects with pure ADDE in a general clinic-based patient cohort.

PURPOSE: A prospective, multisite clinical study (10 sites in the European Union and the United States) evaluated the clinical utility of commonly used tests and tear osmolarity for assessing dry eye disease severity. METHODS: Three hundred fourteen consecutive subjects between the ages of 18 and 82 years were recruited from the general patient population, 299 of which qualified with complete datasets. Osmolarity testing, Schirmer test without anesthesia, tear film breakup time (TBUT), corneal staining, meibomian dysfunction assessment, and conjunctival staining were performed bilaterally. A symptom questionnaire, the Ocular Surface Disease Index (OSDI), was also administered to each patient. Distributions of clinical signs and symptoms against a continuous composite severity index were evaluated. RESULTS: Osmolarity was found to have the highest correlation coefficient to disease severity (r(2) = 0.55), followed by conjunctival staining (r(2) = 0.47), corneal staining (r(2) = 0.43), OSDI (r(2) = 0.41), meibomian score (r(2) = 0.37), TBUT (r(2) = 0.30), and Schirmer result (r(2) = 0.17). A comparison of standard threshold-based classification with the composite severity index revealed significant overlap between the disease severities of prospectively defined normal and dry eye groups. Fully 63% of the subjects were found to be poorly classified by combinations of clinical thresholds. CONCLUSIONS: Tear film osmolarity was found to be the single best marker of disease severity across normal, mild/moderate, and severe categories. Other tests were found to be informative in the more severe forms of disease; thus, clinical judgment remains an important element in the clinical assessment of dry eye severity. The results also indicate that the initiation and progression of dry eye is multifactorial and supports the rationale for redefining severity on the basis of a continuum of clinical signs. (ClinicalTrials.gov number, NCT00848198.).