Low-Level Light Therapy in Association with Intense Pulsed Light for Meibomian Gland Dysfunction

João Heitor Marques,1 Ana Marta,1,2 Pedro Manuel Baptista,1,2 Daniel Almeida,1 Diana José,1 Paulo JM Sousa,1 Irene Barbosa1,2 1Ophthalmology Department, Centro Hospitalar Universitário do Porto, Porto, Portugal; 2Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, PortugalCorrespondence: João Heitor Marques, Centro Hospitalar Universitário do Porto, Largo Prof. Abel Salazar, Porto, Portugal, Email joaoheitormarques@gmail.comPurpose: To study the clinical benefit of low-level light therapy when associated with intense pulsed light for the treatment of meibomian gland dysfunction.Methods: An observational study. Two groups of patients that were treated with IPL were considered: group 1 (31 subjects, 62 eyes), intense pulsed light followed by low-level light therapy and group 2 (31 subjects, 62 eyes) intense pulsed light alone. In both groups, treatments were performed in 3 sessions and subjects were evaluated at baseline and 3 weeks after the last treatment session. Values are shown as mean difference ± standard deviation.Results: We observed a significant improvement in OSDI-12 score and lipid layer thickness, in both groups (− 22.7± 17.5, p< 0.001 in group 1 and − 23.6± 23.8, p< 0.001 in group 2 for OSDI and +18.6 ± 37.0, p< 0.001 in group 1 and +19.9 ± 26.4, p< 0.001 in group 2 for lipid layer thickness). Despite no differences between groups at baseline (p=0.469), only group 1 had a significant improvement in Schirmer test (+1.6± 4.8, p=0.009 in group 1 and +1.7± 6.9, p=0.057 in group 2). No significant side effects were noted. No patient in any group felt subjectively “worse” after the treatment.Conclusion: Intense pulsed light seems effective and safe for the treatment of meibomian gland dysfunction, improving symptoms and the tear film lipid layer. This study shows no strong evidence of the benefit of low-level light therapy, but it shows weak evidence that it may further improve aqueous tear production.Keywords: dry eye syndromes, meibomian gland dysfunction, phototherapy, intense pulsed light therapy, low-level light therapy