Time outdoors has a protective effect against myopia that may be mediated by the high illuminance (brightness) of outdoor light. The importance of children receiving adequate exposure to daylight is now recognized by many specialists,1 but why does bright light protect against myopia?
The primary hypothesis is that bright light stimulates dopamine release in the retina.2 It is well-established that dopamine is released in response to bright light and supports a variety of functions in the retina.3 In animals, experimental myopia is associated with lower levels of dopamine in the eye, and administering dopaminergic compounds can inhibit myopia development and axial elongation.2
The protective effect of bright light against myopia development is not observed when animals are administered a compound that blocks dopamine receptors. That is, when dopamine is unable to act within the eye, the beneficial effect of bright light against myopia is not seen. This further supports that the protective effect of bright light can be attributed, at least in part, to dopamine activity in the retina.4
Overall, there is considerable evidence to support the light-stimulated dopamine hypothesis of myopia control. The exact mechanism through which dopamine signalling modulates eye growth regulation remains unknown. To date, much of the research in this area has been conducted in animals. Additional studies in humans will contribute to our understanding of dopamine’s role in eye growth regulation and refractive error development in children.1
Dopavision’s digital approach to myopia treatment, known as MyopiaX®, uses a scientifically developed light stimulus to excite a subset of photosensitive cells that provide input to dopaminergic amacrine cells in the retina. By stimulating this pathway, MyopiaX® aims to effectively activate the signalling cascade from light exposure to dopamine release. In collaboration with our academic partners, we measured an increase in ocular dopamine in a pre-clinical model after targeted light stimulation. In young adults, contrast sensitivity, a dopamine mediated function, was also significantly increased after exposure to our light stimulus.
Check out our Product and Science pages to learn more about MyopiaX® and our upcoming clinical trial.
1Zhang, J., & Deng, G. (2020). Protective effects of increased outdoor time against myopia: a review. Journal of International Medical Research, 48(3), 0300060519893866.
2Zhou, X., Pardue, M. T., Iuvone, P. M., & Qu, J. (2017). Dopamine signaling and myopia development: what are the key challenges. Progress in retinal and eye research, 61, 60-71.
3Witkovsky, P. (2004). Dopamine and retinal function. Documenta ophthalmologica, 108(1), 17-39.
4Ashby, R. S., & Schaeffel, F. (2010). The effect of bright light on lens compensation in chicks. Investigative ophthalmology & visual science, 51(10), 5247-5253.