Ophthalmotoxicology of polyhalogenated compounds

Polyhalogenated compounds (PHCs), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and per- and polyfluoroalkyl substances (PFAS), are persistent organic pollutants that bioaccumulate in tissues and are increasingly recognized as threats to human health. While their neurotoxic and endocrine-disrupting effects are often described, their potential impact on the ocular system remains underexplored. However, recent evidence suggests that chronic PHC exposure may contribute to a spectrum of ocular pathologies, such as retinal degeneration, cataracts and retinoblastoma. To clarify these emerging risks, this review synthesizes findings at the intersection of toxicology, ophthalmology, and environmental health, highlighting mechanistic insights into how PHCs impair ocular function. Epidemiological studies linking environmental contaminant exposure to visual deficits are discussed alongside experimental data from animal models and in vitro systems, with a particular focus on oxidative stress, mitochondrial dysfunction, endocrine disruption, and altered retinoid signaling as plausible pathways mediating PHC-induced visual toxicity. Given the widespread nature of PHC exposure and the increasing global burden of visual impairment, further research and regulatory oversight are urgently needed to bridge the gap between environmental toxicology and ocular health, ultimately aiming to better understand and mitigate the visual risks posed by these persistent pollutants.