Approval for buiding the classroom has not been obtained.

This trial aims to test the effectiveness and practicality of study in the Bright Classrooms with skylight and artificial light renovation in reducing incident myopia in Chinese primary school children over three years, as compared to children studying in conventional classrooms.

The investigators now propose a cluster-randomized controlled trial of Bright Classrooms to provide a definitive answer as to their effect on the reduction of myopia incidence with the interventions of students studying in bright classroom from skylight and artificial light renovation. The bright classroom trial will be conducted in Jiangxi Province, South-east China via Nanchang University Affiliated Eye Hospital and the artificial light renovation study will be in Zhejiang Province via Eye Hospital, Wenzhou Medical University. Classroom design and build will be supported by leading firm in this space, Velux. If the principal can be proven that such innovative architectural modifications and classroom light renovation successfully prevent myopia, it will provide an evidence-based justification for a broad variety of low-cost retrofits, new build designs and light renovation appropriate for various Chinese settings. These might include larger windows, skylights, artificial lighting and appropriate seating arrangements. Once in place, such architectural and light interventions could benefit children over many years, without extensive and difficult-to-sustain programs of behaviour change. This proof-of-principle project could address a significant global eye health challenge and have significant and sustainable socio-economic impact for China and built environments elsewhere throughout the world.

Schools selected for the trial are: Yifen County: 2 schools, Lichuan County: 2 schools, Yiyang County: 2 schools, Fuliang County: 1 school and Shanggao County: 1 school.

Inclusion Criteria:

• Willingness of parents to give consent
• Membership in randomly-selected classes at the selected schools.

Exclusion Criteria:

• Children without consent from their parents will be excluded.
• Children having myopia (myopic spherical equivalent refractive error of <= -0.5D in one or both eyes) at baseline are excluded from the primary analysis, although they will be included in the secondary analyses, so there will be no need to exclude them from continuing to study with their classmates and use the assigned classroom.

study subjects will be presented by code, and shared with other researchers