This narrative review focuses on the literature investigating light-driven modulations of ocular growth and refractive error development in humans and animal models. The authors also summarize the current knowledge on neurobiological and photoreceptoral mechanisms involved in the putative effect of light against myopia onset and highlight a potential pathway for the translational development of noninvasive light-therapy strategies to halt or delay myopia onset in children.
During this COVID-19 pandemic, toddlers, children, and teenagers alike are exposed to unprecedented amounts of indoor time, sparking concerns over an ever more severe myopia boom. Notwithstanding these unusual circumstances, there is a need for consensus on optimal, feasible, and noninvasive light interventions for myopia prevention in children, whether through increased time outdoors or adapted architectural lighting or light-therapy devices.
Light and Myopia: From Epidemiological Studies to Neurobiological Mechanisms
Arumugam R. Muralidharan, Carla Lança, Sayantan Biswas, Veluchamy A. Barathi, Low Wan Yu Shermaine, Saw Seang-Mei, Dan Milea, Raymond P. Najjar
Myopia is far beyond its inconvenience and represents a true, highly prevalent, sight-threatening ocular condition, especially in Asia. Without adequate interventions, the current epidemic of myopia is projected to affect 50% of the world population by 2050, becoming the leading cause of irreversible blindness. Although blurred vision, the predominant symptom of myopia, can be improved by contact lenses, glasses, or refractive surgery, corrected myopia, particularly high myopia, still carries the risk of secondary blinding complications such as glaucoma, myopic maculopathy, and retinal detachment, prompting the need for prevention. Epidemiological studies have reported an association between outdoor time and myopia prevention in children. The protective effect of time spent outdoors could be due to the unique characteristics (intensity, spectral distribution, temporal pattern, etc.) of sunlight that are lacking in artificial lighting. Concomitantly, studies in animal models have highlighted the efficacy of light and its components in delaying or even stopping the development of myopia and endeavored to elucidate possible mechanisms involved in this process. In this narrative review, we (1) summarize the current knowledge concerning light modulation of ocular growth and refractive error development based on studies in human and animal models, (2) summarize potential neurobiological mechanisms involved in the effects of light on ocular growth and emmetropization, and (3) highlight a potential pathway for the translational development of noninvasive light-therapy strategies for myopia prevention in children.
Muralidharan, A. R., Lança, C., Biswas, S., Barathi, V. A., Wan Yu Shermaine, L., Seang-Mei, S., … & Najjar, R. P. (2021). Light and myopia: from epidemiological studies to neurobiological mechanisms. Therapeutic Advances in Ophthalmology, 13, 25158414211059246.