Research progress on the mechanisms of circadian rhythms and the development of childhood myopia

Myopia has become a global epidemic,with projections indicating that nearly half of the world’s population will be affected by myopia by 2050, positioning it has a significant global functional health concern. Beyond merely impairing vision, myopia also heightens the risk of blinding diseases such as macular degeneration and glaucoma. Although the pathogenesis of myopia is not yet fully elucidated, it is strongly associated with environmental factors, genetic predispositions, and circadian rhythm disruptions. The circadian rhythm plays a pivotal role in the onset and progression of myopia by governing mechanism such as light exposure, dopamine metabolism, and retinal signaling. Light serves as a crucial regulator of the circadian rhythm. Specifically, high light intensity during outdoor activities can effectively stimulate dopamine secretion, thereby inhibiting axial elongation and reducing the incidence of myopia. Conversely, abnormal light patterns, such as exposure to light at night, can disrupt this regulatory process. Moreover, insufficient sleep has been found to be negatively correlated with the incidence of myopia in children. Additionally, key ocular parameters, including axial length and vitreous cavity depth, exhibit pronounced diurnal rhythmic fluctuations. Dopamine, an important neurotransmitter in the retina, is regulated by circadian clock genes and functions to inhibit axial elongation. Both the circadian clock genes and photosensitive pigments within the retina are involved in regulating eye growth. Meanwhile, the autonomic nervous system contributes to this regulation by modulating choroidal thickness and blood flow perfusion. Animal experiments and clinical studies have consistently demonstrated that disrupted circadian rhythms can lead to axial elongation and the progression of myopia. Future research should delve deeper into the causal relationship between circadian rhythm and myopia, the regulatory mechanisms underlying dopamine metabolism, and the functions of circadian clock genes. Such investigation will pave the way for the development of effective strategies for myopia prevention and control.