With great interest, we read the article by Pose-Bazarra et al published in 2021 in Eye (Lond). The authors performed a meta-analysis to compare the effectiveness and safety of different surgical and laser techniques in people with pseudoexfoliation glaucoma [1]. At the outset, we would like to congratulate the authors for writing an informative article with novelty. While we read the article with pleasure, it must be noted that this study raises some thought-provoking issues. Therefore, we wish to have the opportunity to comment respectfully on this article.

Firstly, the authors stated that only six randomized controlled trials (RCTs) were included in this meta-analysis and evaluated the study quality based on the Cochrane Collaboration’s tool. However, when all RCTs were further examined using the same risk assessment tool, we found that Pose-Bazarra et al might have made some mistakes in assessing the risk of bias in the included studies. Therefore, we reassessed the risks of each study and plotted them in Fig. 1A, B. Secondly, the authors state that ten relevant databases were searched for RCTs. However, two studies which published online before the deadline were not included in this meta-analysis [2, 3]. Therefore, other important databases including Wanfang, NLM Gateway, and Web of Science should also be searched to avoid missing original studies. Finally, the authors used an inverse variance random-effects model to pool the data in this review. In our opinion, studies should be combined by using the DerSimonian and Laird random effects model, which considers both within- and between-study variations.

Fig. 1: Risk of bias.
figure 1

A Risk of bias graph. B Risk of bias summary.

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In the past few years, we have seen a substantial increase in the quantity of meta-analyses. The majority, however, have minor or major mistakes that are avoidable by careful adherence to proper methodology. We have to be aware that nowadays clinical practice mostly relies on meta-analyses and guidelines. Thus, they have to be of the highest quality. Only then we can draw the right conclusions. Overall, Pose-Bazarra et al analyzed a valuable issue, but the results of this meta-analysis should be interpreted with caution due to the limitations mentioned above.