Evaluation, diagnosis and grading of severity of MGD

Purpose To evaluate current diagnostic tests and make future recommendations. Methods An evidence-based review of procedures. Results MGD is a common symptomatic disorder leading to associated ocular surface disease including evaporative dry eye. A two stage diagnostic approach is recommended including an assessment of meibomian function based on lid morphology, gland mass, expressibility, lipid layer appearance and tear evaporation. A diagnosis of dry eye is based on measures of tear production and clearance, tear osmolarity, tear film stability and the presence of ocular surface changes revealed by tissue staining and inflammatory biomarkers. Quantification of MGD depends on grading meibum quality and expressibility. Newer, quantitative methods will make grading more accurate in the future and include quantitative meibomian expression, non-invasive meibography, confocal microscopy, video-interferometry and the use of inflammatory biomarkers. Meibomian gland dropout can be to monitor and stratify MGD in clinical trials. Conclusion A provisional severity rating of MGD and MGD-related disease has been proposed as a guide to the selection of treatment and the monitoring of disease progression.