Evaluating the myopia progression control efficacy of defocus incorporated multiple segments (DIMS) lenses and Apollo progressive addition spectacle lenses (PALs) in 6- to 12-year-old children: study protocol for a prospective, multicenter, randomized controlled trial

Background: Myopia is increasing in prevalence and is currently recognized as a significant public health issue worldwide, particularly in China. Once myopia develops, appropriate clinical interventions need to be prescribed to slow its progression. Currently, solid evidence indicates that myopic defocus (MD) retards eye growth and myopia progression. However, no clinical trial has compared the outcomes of different MD spectacle lenses in the same observational group, especially in mainland China. The aim of the present study is to compare the myopia control efficiency of two different MD spectacle lenses, i.e., defocus incorporated multiple segments (DIMS) and Apollo progressive addition spectacle lenses (PALs). Methods: The trial is a 3-year, prospective, randomized, multicenter clinical trial of school children with DIMS and PALs. A total of 600 Chinese primary school children aged 6-12 years will be recruited, and each group is intended to include 300 subjects. The inclusion criteria are myopia between −1.00 and −5.00 D and astigmatism ≤1.50 D. The primary outcomes are cycloplegic spherical equivalent refraction (SER), measured at 6-month intervals, and the changes between groups compared over the study period. The secondary outcomes are axial length, compliance and questionnaires related to wearing experiences. The exploratory outcomes include ocular biometric measures, peripheral refraction, binocular vision, and accommodation. Discussion: The present study is the first randomized controlled trial of DIMS and PALs treatment for primary school children with myopia in China. The results will indicate whether and how much of different MD mechanisms approach retards myopia progression and axial elongation. In addition, the comparison will provide information on the clinical effectiveness and safety of DIMS and APLs, including wearing experiences, visual functions, etc.Trial registration: Chinese Clinical Trial Registry (ChiCTR) Identifier: ChiCTR1900025645. Date of registration: 3 September 2019. http://www.chictr.org.cn/showproj.aspx?proj=42927