A duration-dependent interaction between high-intensity light and optical refocus in the drive for myopia control

Abstract

PURPOSE To evaluate the duration-dependent and synergetic impact of high-intensity light (HL) and optical refocus (RF) on lens-induced myopia (LIM) development in chickens. METHODS Myopia was induced in one eye in chicks (10 groups, n=126) from day 1 post- hatching (D1) until D8 using -10D lenses. Fellow eyes remained uncovered as controls. Nine groups were exposed daily to continuous 2 hours (h), 4h, or 6h of either HL (15,000 lux); RF (removal of -10D lens); or both (HL+RF). One group served as the LIM group without any interventions. Ocular axial length (AL), refractive error, and choroidal thickness were measured on D1, D4, and D8. Outcome measures are expressed as inter-ocular difference (IOD= experimental - control eye) ±SEM. RESULTS By D8, LIM increased AL (0.36±0.04 mm), myopic refraction (-9.02±0.37D), and choroidal thinning (-90.27±16.44 µm) in the LIM group (all, P CONCLUSION Daily exposure to 2h, 4h, or 6h of HL, RF, or HL+RF reduced lens-induced myopic refraction in a duration-dependent manner in chickens. Only 6h of HL+RF completely stopped LIM development. The synergetic effect of HL and RF is dependent on the duration of the interventions.