A Comparative Study of Intense Pulsed Light with Two Different Filters in Meibomian Gland Dysfunction: A Prospective...

Objectives: To compare the long-term efficacy and safety of intense pulsed light (IPL) treatments using a 590-nm and an acne filter. Methods: In this prospective, randomized, paired-eye trial study, 30 patients with moderate and severe meibomian gland dysfunction (MGD) were followed up for at least one month after their last treatment. Group A received IPL treatment with an acne filter, a type of notch filter that blocks wavelengths between 600 and 800 nm, allowing IPL to emit wavelengths between 400-600 nm and 800-1200 nm. Group B received treatment with a 590 nm filter, a type of cut-off filter that blocks wavelengths below 590 nm. Clinical parameters, including tear osmolarity, matrix metalloproteinase (MMP)-9 expression, tear break-up time, ocular surface staining scores, Schirmer's test I, lid margin telangiectasia scores, MG expressibility/secretion scores, and Ocular Surface Disease Index scores, were measured at baseline, 1, 6, and 12 months after their last treatment. Results: In the linear mixed model, significant time effects on all clinical parameters, except for MMP-9 grades and Schirmer's test I results, were observed within each group. However, interactions between time points (baseline, 6 months, 12 months) and groups (Group A, B) were not significant. The generalized estimating equation model showed no significant interaction between time points and groups for MMP-9 positivity; however, a significant time effect on MMP-9 positivity was observed in Group A, with a decrease at 12 months after their last treatment when compared to baseline and 6 months. Conclusions: The IPL treatment modality for moderate to severe MGD demonstrated a significant therapeutic effect for one year under strictly controlled self-administration of other treatments. IPL treatment using acne filter is a promising treatment option for reducing MMP-9 positivity in MGD patients.