Supplementation with high spatial frequency in visual environments for Chinese children to arrest myopia: A proof-of-concept exploratory study

Purpose: This randomised clinical trial investigated whether a high spatial frequency enhancing classroom presenting outdoor scenes (outdoor scene classroom, OSC) can arrest myopia development in children. Methods: This is a two-arm, parallel, non-blinding, cluster randomised trial. The trial was single centre, school-based and conducted in Lijiang Shiyan School, Lijiang, Yunnan. China. Grade 3 primary school students were recruited. The intervention was the OSC, designed to resemble the natural outdoor environment by adorning the walls with wallpaper featuring natural images with high spatial frequency content. The primary outcome was 1-year myopia incidence. Secondary outcomes were 1-year change of spherical equivalent refraction (SER) and 1-year change in axial length (AL). Results: The primary outcome, myopia incidence, was not significantly different between the OSC group and the traditional classroom (TC) group, (14.1% vs 16.9%, p = 0.42). The secondary outcomes showed a protective effect of OSC. The mean ± SE of the 1-year change in SER was −0.47 ± 0.04 and −0.67 ± 0.04 D in the OSC and TC groups, respectively (p < 0.001). The mean ± SE 1-year change in AL was 0.25 ± 0.01 and 0.31 ± 0.02 mm in the OSC and TC groups, respectively (p = 0.02). In multivariable analysis, the TC group had a 0.21 D (95% CI −0.30, −0.11) more myopic shift than the OSC group, after controlling for age, gender and baseline refractive error. Conclusions: OSC was protective in slowing myopic shift. Large implementation of OSC provides an alternative strategy to increased time outdoors in myopia prevention and provides an approach that involves less disruption to school routines.