Intense pulsed light for meibomian gland dysfunction: a systematic review and meta-analysis

Intense pulsed light therapy (IPL) is a new method being used to treat meibomian gland dysfunction (MGD) globally. With an increasing number of studies being published, it is necessary to consider additional factors related to treatment. This review aims to investigate the efficacy and safety of IPL for the treatment of MGD.

The PubMed, EMBASE, Web of Science, Cochrane Library, Google Scholar, China National Knowledge Infrastructure (CNKI), Wanfang, VIP, and SinoMed databases were searched through February 24, 2020. Randomized clinical trials and cohort studies comparing IPL+ meibomian gland expression (MGX) or IPL alone with control groups were included. The weighted mean difference (WMD) was calculated to analyze the Ocular Surface Disease Index (OSDI) score and Standard Patient Evaluation of Eye Dryness (SPEED) score, and the standard mean difference (SMD) was calculated to analyze the tear breakup time (TBUT). Heterogeneity was quantified by the I² statistic ranging from 0 to 100%, and a random effects model was used in this meta-analysis. All analyses were performed by RevMan 5.3. All p values were calculated by the t test, and p values were regarded as statistically significant at p < 0.05. The Cochrane Collaboration's tool for assessing risk of bias was used to identify and evaluate bias in the literature.

Nine studies with a total of 539 patients were included. Eight studies examined TBUT, six examined OSDI scores, and four examined SPEED scores. IPL combined with MGX showed superiority regarding the TBUT (SMD 2.33, 95% CI 1.04-3.61), and OSDI scores (WMD 11.93, 95% CI - 17.10 to - 6.77), with high heterogeneity. The SPEED scores were not significantly different.

IPL combined with MGX may be an effective and safe treatment for MGD, but it cannot improve all symptoms. IPL alone is not superior to MGX. The efficacy is also affected by the number and average frequency of treatments. The efficacy of IPL may decrease within 6 months after the last treatment, so it should be considered a long-term adjuvant therapy combined with MGX. When patients receive 3 or 4 treatments (once every 3-4 weeks), a return visit at 6 months after the last treatment is required.