When nights are no longer dark: Aging and light pollution reshape visual system rhythms

Retinal aging is a progressive process influenced by both intrinsic circadian timekeeping mechanisms and environmental factors, including artificial light exposure. Light pollution, characterized by prolonged and dysregulated illumination, disrupts circadian clock function and has emerged as a critical yet underexplored driver of visual system decline. Here, we investigated the interplay between circadian regulation, chronic light pollution - implemented as dim nocturnal light and blue light exposure - and age-dependent deterioration of the visual system. Using a Drosophila model, we demonstrate that exposure to light-polluted conditions accelerates retinal aging. Chronic disruption of the light-dark cycle impairs rhythmic processes essential for visual system homeostasis, including synaptic plasticity and daily modulation of glial activity. These alterations are accompanied by a progressive decline in retinal physiology and reduced efficiency of visual information processing. Our findings indicate that circadian desynchronization induced by light pollution compromises temporal regulation of neuronal and glial function, thereby exacerbating age-dependent degeneration of the visual system. This study highlights the critical role of circadian organization in maintaining retinal function and identifies light pollution as a potent environmental factor accelerating visual aging.