Background Dental examination lamps (DELs) enhance visual acuity and focus during surgical procedures and clinical exams in dental clinics. Prolonged exposure to high-intensity light can cause thermal burns and toxicities in eyes. This study examined the risk of damage to the eyes from blue radiation emitted by DELs, considering lens spectral transmission at different ages.
Methods The spectrum irradiance of 14 types of DELs manufactured by 14 companies was measured using a Hopoocolour OHSP350S spectrometer. The blue weighted radiances (LB) were computed for direct viewing at 30 cm and indirect viewing at distances of 30 cm, 50 cm, and 100 cm. The maximum daily exposure duration (tmax) was computed only for the direct viewing of light across different ages (1–70 years old).
Results LED-based DELs have peak blue spectral radiances of between 440 and 450 nm. Indirectly viewing any of the tested DELs is safe. DEL characteristics and human eye light transmission at different ages determined the direct viewing LB values as ranging from 3 to 483 W.m-2.sr-1. Luna, with the lowest blue light radiance of 0.09 ± 0.05, has the longest tmax value. The shortest tmax value was obtained with SKEMA 6, which had the highest mean blue light radiance of 4.75 ± 3.41.
Conclusion Retinal tissue damage from cumulative direct light viewing decreases from 1 to 70 years of age. This decrease in retinal tissue damage rises with blue light radiance. The maximum acceptable ocular exposure limits for DELs and ages were computed to inform decisions on avoiding blue light.