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High-intensity blue light from dental light-curing units concentrates in the 400–500 nm range, which is absorbed by the retina and can produce photochemical injury; systematic reviews and safety studies identify retinal degeneration/damage as the primary ocular hazard of these devices, not anterior-segment problems such as iritis, conjunctivitis, or cataract [Alasiri, 2019, PMID 30983826; Price, 2016, PMID 27003737].