Low-level light therapy as an adjunct to intense pulsed light for lipid layer thickness improvement in meibomian...

To determine whether adjunctive low-level light therapy (LLLT) provides additional benefit when combined with intense pulsed light (IPL) for meibomian gland dysfunction (MGD).

In this prospective, randomized, double-blind, sham-controlled clinical trial, 58 participants with MGD grade 2 or higher were randomized to receive four weekly IPL sessions combined with either active LLLT (IPL + LLLT) or sham LLLT (IPL alone). The primary outcome was change in lipid layer thickness at weeks 2, 4, 12, and 24. Secondary outcomes included meibomian gland function, non-invasive tear breakup time, Ocular Surface Disease Index, ocular surface staining, and tear cytokines (interferon-γ, interleukin [IL]-1β, IL-6, and tumor necrosis factor-α).

Both groups demonstrated significant within-group improvements over time across most outcomes. Longitudinal analysis showed a significant group-by-time interaction for lipid layer thickness. Between-group differences emerged at week 12 and persisted through week 24. At week 24, the IPL + LLLT group demonstrated a greater mean increase in lipid layer thickness than the IPL-alone group (16.17 ± 8.55 nm vs. 5.86 ± 7.50 nm), corresponding to a model-estimated between-group difference of 10.3 nm (95% CI, 6.1-14.5). No significant between-group differences were observed for symptoms, tear stability, ocular surface staining, meiboscore, or inflammatory biomarkers.

Adjunctive LLLT was associated with a sustained increase in lipid layer thickness compared with IPL alone. However, this structural improvement did not translate into superior symptomatic or inflammatory outcomes, suggesting that adjunctive LLLT may enhance structural tear film parameters without providing additional short-term clinical or anti-inflammatory benefit.