The role of circadian rhythms in the pathogenesis of myopia

Myopia is a complex ocular disorder arising from the interaction of genetic predisposition and environmental cues that regulate eye growth. Increasing evidence indicates that the circadian timing system plays a critical role in ocular development and refractive homeostasis. The retina, choroid, and sclera possess intrinsic molecular clocks that generate rhythmic oscillations in gene expression, neurotransmitter release, and tissue physiology. Disruption of these ocular circadian rhythms has been implicated in abnormal axial elongation through pathways involving dopamine and melatonin signaling, light-dependent retinal pathways, and diurnal fluctuations in intraocular pressure. In this review, we summarize current knowledge of the molecular mechanisms underlying circadian regulation in ocular tissues and discuss how environmental light exposure and sleep–wake cycles modulate these processes. We further integrate evidence linking rhythmic alterations in retinal, choroidal, and scleral function to myopia development. Finally, we propose mechanistic frameworks through which circadian dysregulation may contribute to myopia onset and progression, highlighting potential molecular targets for rhythm-based intervention strategies.