In vivo confocal microscopy classification in the diagnosis of meibomian gland dysfunction

Abstract

Aim: Meibomian gland dysfunction (MGD) is one of the most common disorders in ophthalmology. The aim of this study was to evaluate the use of this in vivo confocal microscopy (IVCM)-MGD description to classify patients affected by clinical MGD and measure the correlation with standard clinical criteria and subjective symptoms.

Methods: One hundred eyes of 100 patients suffering from MGD and 15 eyes of normal subjects were included. A comprehensive evaluation with the ocular surface disease index (OSDI), Schirmer test, tear break-up time (TBUT), tear osmolarity, Oxford score, Meibomian gland expression, palpebral IVCM, and meibography was performed. Then each patient was classified using a new IVCM classification: type 0 for normality, type 1 for meibum obstruction, type 2 for inflammation, and type 3 for fibrosis.

Results: The mean age of patients was 52 ± 20 years old, the OSDI was 38 ± 23, the BUT 5 ± 2.6 s, the Schirmer test 13 ± 7 mm, tear osmolarity 300 ± 11 osmol/L, the Oxford score 0.5 ± 0.6, the meibum expression score 1.7 ± 1.02, and the meibography score 1.3 ± 0.9. The IVCM MG classification of the 15 normal subjects was 0. For MGD patients, 29% were in type 1, 40% were type 2, and 31% were type 3. The patients in IVCM MG type 2 had a higher OSDI (p = 0.001) compared with the other types. There was a strong correlation between the IVCM score and the meibography score (r = 0.71 p < 0.0001).

Conclusion: This new IVCM classification provided a practical pathophysiological system for MGD. By giving objective criteria, this IVCM classification may help advance the understanding of patients' symptoms and enhance treatment effectiveness in MGD.

Fig. 1

MGD staging with meibography: a stage 0, no gland loss; b stage 1, loss <33%; c stage 2, loss between 33 and 66%; d stage 3, loss >66%

Fig. 2

MGD staging analyzed with in vivo confocal microscopy (IVCM). a type 0 in IVCM, normal meibomian glands; b type 1 in IVCM, lumen obstruction with minimal inflammation; c type 2 in IVCM, intraepithelial, and interglandular inflammation; d, type 3 in IVCM, fibrosis with epithelium destruction