Outcomes in randomized controlled trials on slowing myopia: A systematic review.

Introduction: This review aims to analyse the application of the measure methods and measure contents of the outcomes reported in studies on slowing myopia, and the associations between outcomes and study characteristics.

Methods: Publications were identified by a search of seven electronic databases including China National Knowledge Infrastructure, China Biology Medicine, Wanfang database, CQVIP database, PubMed, Cochrane Library and Excerpta Medica Database, for relevant terms like myopia and randomized controlled trial from construction to Sept. 15th, 2023. The basic information of studies was extracted, including publishing time, region, intervention duration, sample size, intervention and outcome. Additionally, the measurements of outcomes were explored. The risk of bias of all studies included were assessed.

Results: Altogether, 599 randomized controlled trials were included, including vision (52.75 %), refraction (64.94 %), eye axial length (47.25 %) and response rate (38.23 %). Since 478 studies (79.80 %) were published in Chinese, the included studies were divided into subgroups according to the study language. The number of research published in Chinese was surged since 2005. The rate of refraction was gradually increased from 27.27 % before 2005 to 71.08 % in the past 2 years. 121 studies in English were included in this study. The usage frequency of refraction was ≥75 % in each period and that of eye axial length kept at more than half. In the studies lasting >6 months, the usage frequencies of refraction and axial length were >90 %. They accounted for 91.30 % and 82.61 % in the studies using contact lenses, and both 94.12 % in the studies using spectacles.

Conclusion: More and more attention is paid in slowing myopia, and the reported outcomes are diverse. Based on the analysis of the outcomes, there is a lack of an agreed-upon standardised set of outcomes in clinical trials for slowing myopia.