Natural daylight exposure stimulates retinal dopamine release, which inhibits axial elongation and reduces myopia progression.

Study: Myopia Progression Risk: Seasonal and Lifestyle Variations in Axial Length Growth in Czech Children

Kids' eyes grew longer in winter when there was less sunlight, and shorter in summer when there was more sunlight — suggesting that being outside in bright light may help keep eyes from getting too long and causing nearsightedness.

Study: Retinal Dopaminergic Activation and Oxidative Stress Reduction Induced by Green Landscape Exposure: Evidence from a Controlled Myopia Study

Spending time in green, sunny places helped people see better, and scientists found this might be because their eyes made more dopamine, which helps stop the eye from growing too long — a main cause of nearsightedness.

Study: The association between time spent outdoors and myopia in children and adolescents: a systematic review and meta-analysis.

Spending more time outside is linked to a lower chance of kids becoming nearsighted, and the more time they spend outdoors, the better their eyes seem to develop. This supports the idea that daylight helps stop eyes from growing too long.

Study: Contribution of chemical and electrical transmission to the low delta-like intrinsic retinal oscillation in mice: A role for daylight-activated neuromodulators.

The study shows that sunlight triggers the release of dopamine in the eye, which changes how eye cells communicate in a way that’s known to slow the eye from growing too long—this is what causes nearsightedness. So yes, sunlight helps by making dopamine, which stops the eye from getting too long.