Peripheral defocus spectacle lenses versus single‐vision spectacle lenses for myopia control: Systematic review and meta‐analysis

Aims/Purpose: Myopic children wearing traditional single‐vision lenses (SVL) will continue to increase in nearsightedness as eye growth occurs. However, peripheral defocus lenses (PDL) are specialized spectacles based on the retinal‐defocus theory, designed to slow down the progression of myopia. Therefore, we aimed to perform a meta‐analysis exploring the effectiveness of PDL and SVL in controlling myopia. Methods: We searched PubMed, Embase, Cochrane, Web of Science, Epistemonikos and BVS for studies comparing the PDL to SVL in children and adolescents with myopia. Outcomes were spherical equivalent refraction (SER) and axial length (AL). The RoB 2 tool was used to assess the risk of bias. Results: We included 673 patients from 5 randomized clinical trials. PDL was used to control myopia in 403 (59,9%) patients. The mean age was 9.4 years old. Follow‐up ranged from 6 to 12 months. In the pooled analysis, the SER (RR 4.41; 95% CI 1.76, 11.08; I2 = 0%) and AL (RR 28.10; 95% CI 5.57, 141.58; I2 = 18%) was lower in patients using PDL compared to SVL. In the segment analysis, all segments showed a deceleration of the SER of PDL when compared to SVL. The 6 month was the only one to show a result with low heterogeneity (WMD ‐0.19; 95% CI ‐0.26, ‐0.13; I2 = 21%). The analysis at 12 months showed substantial heterogeneity (WMD ‐0.35; 95% CI ‐0.44, ‐0.26; I2 = 57%). When analyzing AL, it can be seen that PDL grows less than SVL in all the segments analyzed. The differences between 6 months (WMD 0.11; 95% CI 0.22, 0.19; I2 = 88%) and 12 months (WMD 0.14; 95% CI 0.10, 0.17; I2 = 70%) were small and with significant heterogeneity. Conclusions: PDLs were associated with more effectiveness at slowing down the progression of myopia, as assessed by both spherical equivalent and axial growth. The substantial heterogeneity between the studies suggests the need for additional research without conflict of interest bias to confirm these results and understand the variations in the effects of the different PDL designs.