Shanghai Time Outside to Reduce Myopia trial (STORM): design and baseline data.

IMPORTANCE: Myopia is a major public health concern worldwide, while outdoor time is indicated to be protective against the onset of myopia.

BACKGROUND: To describe the methodology and baseline data of the Shanghai Time Outside to Reduce Myopia trial (STORM).

DESIGN: A 2 year, school-based, prospective, cluster randomized trial.

PARTICIPANTS: Children from grade I and II classes of 24 schools from 8 districts in Shanghai, China, were randomized to either a control group, a test group I (40 minute outdoor time/day) or test group II (80 minute outdoor time/day).

METHODS: At baseline and annual intervals, cycloplegic autorefraction and axial length measurement will be performed. Time outdoors and light exposure will be monitored via parent/carer questionnaires and a wearable device.

MAIN OUTCOME MEASURES: Spherical equivalent, prevalence of myopia and time outdoors in each group.

RESULTS: A total of 6295 eligible children (age 7.2±0.7 yrs (6-9 yrs)) were randomized to control (n=2037), test group I (n=2329) and test group II (n=1929). At baseline, spherical equivalent was +0.98±1.02D, +1.02±1.02D and +1.00±0.99D(p=0.708), myopia prevalence was 8.9%, 7.7% and 7.8% (p=0.270) and time outdoors was 58.5±35.8, 59.8±34.7 and 58.5±35.3 mins/day (p=0.886) for control, test group I and II respectively.

CONCLUSIONS AND RELEVANCE: Myopia prevalence was high at nearly 8 to 9% in school children aged 7 years in Shanghai, China. The current trial will help evaluate if increased time outdoors has a role to play in reducing the incidence of myopia and/or slow the progression of myopia. This article is protected by copyright. All rights reserved.