Changes in the expression of matrix metalloproteinase-9 after intense pulsed light therapy combined with meibomian gland expression in moderate and severe meibomian gland dysfunction

Purpose To evaluate the combined effect of intense pulsed light (IPL) therapy and meibomian gland expression on extracellular matrix metalloproteinase-9 (MMP-9) levels and clinical outcomes of moderate and severe meibomian gland dysfunction (MGD) treatment. Methods This retrospective study was conducted on 45 eyes of 23 patients with moderate and severe MGD. Each eye underwent three IPL sessions and meibomian gland expression at 2-week intervals. In this study the evaluated parameters included tear film break-up time (TBUT), corneal and conjunctival fluorescein staining scores, biomicroscopic examination of lid margins and meibomian glands, ocular surface disease index (OSDI) questionnaire score, and extracellular MMP-9 levels using the immunoassay device before and two weeks after the last treatment session. Linear mixed model and generalized estimating equations model were used to evaluate possible differences. Results There were significant improvements in TBUT (P < 0.001), SICCA ocular staining score (P = 0.008), Oxford staining score (P = 0.023), lid margin irregularity (P < 0.001 for upper and lower eyelids), lid thickness (P < 0.001 for upper and lower eyelids), meibomian gland plugging (P = 0.010 and P = 0.012 for upper and lower eyelids), meibum color (P = 0.044 and P < 0.001 for upper and lower eyelids), meibum consistency (P < 0.001 for upper and lower eyelids), MGD grade (P < 0.001), and OSDI questionnaire score (P < 0.001). Incidence of positive results for MMP-9 immunoassay significantly decreased from 84.0% to 56.0% (P = 0.031) after treatment. Conclusion In patients with moderate to severe MGD, three sessions of IPL combined with meibomian gland expression improved objective findings, subjective symptoms, meibomian gland function, and MMP-9 immunoassay results. The results support the combination of IPL and meibomian gland expression for treating moderate to severe MGD.