Studies using concentric ring bifocal and peripheral add multifocal contact lenses to slow myopia progression in school-aged children: a meta-analysis

Methodological quality of the review: High confidence

Author: Shi-Ming Li, Meng-Tian Kang, Shan-Shan Wu, BoMeng, Yun-Yun Sun, Shi-Fei Wei, Luoru Liu, Xiaoxia Peng, Zhuo Chen, Fengju Zhang and Ningli Wang

Region: New Zealand, Hong Kong, Japan, USA, China, Spain

Sector: Myopia

Subsector: Myopia treatment

Equity focus: No

Study population: School-aged children

Type of programme: School based

Review type: Other review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background: Over the past few decades, myopia prevalence has increased dramatically worldwide, especially in Asia where it has reached an epidemic level. This rapid increase is particularly remarkable in school-aged children who have shown a younger age of myopia onset and an increasing prevalence of high myopia. Many attempts have been made to control myopia progression in school-aged children, such as optical corrective devices, pharmacological interventions, and even methods of traditional Chinese medicine. However, few strategies have achieved satisfactory results in terms of clinical significance and safety.

Objectives: The objective of this study was to evaluate the effect of soft contact lens with concentric ring bifocal and peripheral add multifocal designs on controlling myopia progression in school-aged children.

Main findings: A total of eight studies composed of five randomised controlled trials (RCTs) and three cohort studies, with a total of 587 myopic children, were included. Compared with the control group, concentric ring bifocal soft contact lenses showed less myopia progression, with a weighted mean difference (WMD) of 0.31 D (95% CI, 0.05-.57 D, P=0.02) and less axial elongation with a WMD of -0.12 mm (95% CI, approximately -0.18 to -0.07 mm, P<0.0001) at 12 months. Relative to the control group, peripheral add multifocal soft contact lenses showed less myopia progression, with a WMD of 0.22 D (95% CI 0.14-0.31 D, P<0.0001) and less axial elongation of -0.10 mm (95% CI -0.13-0.07 mm, P<0.0001) at 12 months, respectively. The soft contact lenses with concentric ring bifocal and peripheral add multifocal designs produced additional myopia control rates of 30-38% for slowing myopia progression and 31-51% for lessening axial elongation within 24 months.

Methodology: Inclusion criteria consisted of: 1) study type: given the paucity of available evidence addressing the question of this study and previously reported comparable effect in randomised controlled trials (RCTs) and cohort studies, both, were included; 2) study participants: 6- to 18-year-old school-aged children with a diagnosis of myopia; 3) interventions: SCLs with special design in the experimental group, and single vision soft contact lenses or spectacles in the control group since both of them have been reported to have no effects on myopia progression and axial elongation,13,24,25; 4) outcomes: myopia progression (change in spherical equivalent) and axial elongation (change in axial length) at different visits.

Two reviewers (SML, SSW) independently searched Medline (1966 to May 2016), Embase (1950 to May 2016), and the Cochrane Library (up to May 2016) using the following keywords: myopia, contact lens, child, myopia progression, axial length, refractive error, clinical trial and relevant free terms. Furthermore, we searched the reference lists in the retrieved articles for additional trials, and used Science Citation Index to find studies that had cited the identified trials. Chinese Clinical Trial Registry, WHO International Clinical Trials Registry Platform and ClinicalTrials.gov were also retrieved for ongoing trials. There were no language restrictions in searching for these trials. Data was independently extracted by two reviewers (SML, SSW) using a customised form. We contacted the authors of included studies for missing data, if needed, and used GetData Graph Digitizer 2.24 (http://getdata-graph-digitizer.com) to read data of different follow-up periods, which were only illustrated in figures. Quality assessment of all included studies was independently performed by two reviewers (SML, SSW) using the Jadad score for RCTs. Analysis: Differences in myopia progression and axial elongation between two groups were expressed as mean differences (experimental group minus control group, Cochrane Handbook 5.1.0, 9.2.3.1) and 95% confidence intervals (CI).

Applicability/external validity: The authors highlighted potential limitations which need to be considered for external use of the findings: the present results were based on data from both randomised controlled trials and cohort studies. Most studies have been conducted with White children. Most of the studies have included children with low myopia and observed them with different follow-up periods.

Geographic focus: This review was conducted in high income countries only and on White children.

Summary of quality assessment:

There is high confidence in the conclusions about the effects of this review. Authors used rigorous methods to conduct the review.