Abstract
Purpose :
Spatial frequency spectra of the environment may have an impact on human myopia. This randomized clinical trial aimed to assess whether mimicking outdoor scene by changing classrooms’ spatial frequency spectra can prevent and control childhood myopia.
Methods :
This is a two-arm, parallel, cluster randomized trial conducted in Lijiang, Yunan, China (Chinese Clinical Trial Registration Number: ChiCTR2000040704). As shown in Figure 1a, 912 graded 3-4 students from 18 classes in one school were randomized to the outdoor scene classroom group (OSCG), decorated with wall papers/coverings of nature outdoor scenes (Figure 1b), and the traditional classroom group (TCG), classrooms with white wall and ceilings. The primary outcome is change of cycloplegic spherical equivalent (SER) from baseline at one year, and secondary outcomes at one year are change of axial length (AL), incidence of myopia (defined as SER ≤-0.50D). All analyses were based on the eye with worse SER at baseline. T-test and Chi-squared test were used for continuous and categorical measures respectively. Two-sided P<0.05 was considered statistically significant.
Results :
As shown in Table 1, two treatment groups were similar in age, gender, baseline SER, AL, and baseline myopia prevalence. Among all participants completed one year follow-up (92%), OSCG showed smaller myopic shift than TCG (-0.49 D vs. -0.57 D, p=0.03). Among children without myopia at baseline, the one-year myopia incidence was similar (17.9% in OSCG vs. 17.0% in TCG, p=0.75). In subgroup analyses stratified by baseline refractive error status, baseline hyperopic (SER≥1.00D) students in OSCG had significantly less myopic shift (-0.26 D vs. -0.40 D, p=0.007) and less AL elongation (0.15 mm vs. 0.22 mm, p=0.04); while such significant difference was not found in students with baseline emmetropia or myopia (Table 1).
Conclusions :
This large clinical trial found outdoor scene classroom had protective effect in preserving hyperopia reserve in hyperopic students, suggesting changing classrooms’ spatial frequency spectra may help prevent myopia onset. However, there seemed to be no effect of slowing down myopia progression. Follow-up of these students are ongoing to evaluate the long-term effect of outdoor scene classroom on myopia incidence and progression.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.