Light-at-night exposure drives myopia via melanopsin signalling

Mar 2, 2026Science China. Life sciences

Exposure to light at night may cause nearsightedness through a light-sensing pathway

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Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Light-at-night (LAN) exposure is associated with increased myopia risk, as shown in both murine models and human epidemiological analysis.

LAN exposure disrupts core circadian clock gene expression in mouse models.
Changes in gene expression are linked to axial elongation in the eyes.
Melanopsin-knockout mice show resistance to myopic changes caused by LAN.
Epidemiological analysis indicates that LAN exposure increases the risk of myopia onset in humans.
These findings suggest a connection between environmental light exposure and myopia development.

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Myopia poses a growing global public health challenge, with its underlying mechanisms not yet fully understood. While insufficient daytime light exposure is a recognized protective factor, the role of nighttime light exposure remains contentious. Through a murine model, we uncover a novel melanopsin-dependent pathway by which light-at-night (LAN) exposure disrupts the expression of core circadian clock genes (including Arntl, Cry1, Per1, and Per2) and downregulates melanopsin expression in intrinsically photosensitive retinal ganglion cells (ipRGCs). These alterations are associated with axial elongation. Crucially, melanopsin-knockout mice exhibit resistance to myopic changes induced by LAN, indicating that melanopsin-dependent pathways mediate ocular growth responses. Supporting these experimental findings, our epidemiological analysis demonstrates that LAN exposure significantly increases the risk of incident myopia onset in humans. Together, these results establish a functional link between environmental light exposure and the molecular pathogenesis of myopia, identifying LAN as a modifiable risk factor for myopia. Our study provides important insights into the light-mediated myopia development and suggests melanopsin signaling as a potential target for preventive and therapeutic strategies.

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Light-at-night exposure drives myopia via melanopsin signalling

Abstract

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