Alternation of Lipidomic in the Meibomian Gland After Exposure to Intense Pulsed Light in Patients With Meibomian Gland Dysfunction and Suggestions for Applications of 3PM Medicine
Authors: Zhao Hui , Ou Shang-Kun , Tang Li-Ying , Shao Yi , Wu Shi-Nan , Xiao Dong , Cheng Zhe , Peng Jie , Hu Hua-Ying 
Published: August 2021

Abstract
Importance: Aside from the clinical index, there is no established criterion for assessing the effectiveness of intense pulsed light (IPL) in treating meibomian gland disease.Objective：To determine if there is an association between changes in the meibum lipidomic profiles and alleviation of clinical signs in patients with meibomian gland dysfunction (MGD) who are treated with IPL. To provide predictive, preventive and and personalized medical programs for MGD patients. Design: This is an observational Study. Patients were followed for up for 6 months from January 1, 2019.Setting: This is a single center, human-oriented clinical and basic research study.Participants: Adult patients, who were diagnosed with MGD and had not received any alternative treatments for at least 3 months, were enrolled in the study. Exposures: Each patient received a series of three treatments at 3-week intervals. The meibum was collected before the first treatment (T0) and the third treatment (T2). All enrolled patients completed the whole examination and treatment. The meibum of randomly assigned 26 patients and 10 healthy volunteers was chosen for performing the lipid analysis using LC-MS/MS. Main Measures: The following information from each patient was recorded: tear break-up time (BUT), average tear BUT, tear meniscus height, assessment of the lid margin, bulbar redness, meibomian gland opening position, corneal fluorescein staining, meibomian gland drop, meibomian gland expressibility, and meibum quality.Results: A total of 191 patients’ right eyes were enrolled in the study, including 95 females (49.7%) and 96 males (50.3%), with a median age of 53 years (range: 28–85 years). IPL increased the BUT (P<0.0001, t=7.9, df=380), average tear BUT (P<0.01, t=2.774, df=374.5), and tear meniscus height (P<0.01, t=2.642, df=367.1). At the same time, IPL improved bulbar redness (P<0.0001, t=12.95, df=380) and corneal fluorescein staining (P<0.0001, t=4.147, df=380). Furthermore, following IPL treatment, the meibomian gland expressibility (MGE) and meibum quality were significantly improved (from 1.342±0.05815 to 0.9354±0.03922, P<0.0001, t=5.798, df=380 and from 1.266±0.04969 to 0.8639±0.03318, P<0.0001, t=6.733, df=380, respectively). Lipidomic analysis of the meibum characterized the changes in lipid profiles induced by IPL. Conclusion: IPL treatment offers a novel approach to markedly improve the treatment of patients with MGD due to correction of altered lipid profiles. The changes in lipid expression profiles are potential indexes to evaluate the therapeutic effectiveness of IPL treatment or other treatments on MGD. The lipid changes that are pertinent include: LPC(18:2)+HCOO, OAHFA(18:1/34:1)-H, TG(16:0/18:2/20:5)+H, and etc.. Therefore, accurate evaluation of the changes of lipid expression profile in patients with MGD can be used as a predictive, preventive, and personalized medical method.