Potential retinal blue hazard from dental examination lamps across different ages.

Abstract

Dental examination lamps (DELs) enhance visual acuity and focus during surgical and clinical examination in dental clinics. However, prolonged exposure to high-intensity light can cause ocular thermal burns and toxicity. This study examined the risk of damage to the eyes from blue radiation emitted by DELs, considering lens spectral transmission across different age groups. The spectral irradiances of 14 DELs manufactured by 14 companies were measured using a spectrometer. The blue light-weighted radiances (L_B) were computed for direct viewing at 30 cm and indirect viewing at 30, 50, and 100 cm. The maximum daily exposure duration (t_max) was computed only for the direct viewing of light across different age groups (1-70 years). LED-based DELs exhibited peak blue spectral radiances between wavelengths of 440 and 450 nm, with illumination levels ranging from 2400 to 89 151 lux. Indirect viewing of the diffuse-reflected light from all the tested DELs was found to be safe. However, long exposures from unprotected viewing of a direct beam may exceed the accepted exposure limits. In the case of direct viewing, the blue light radiance (L_B) varied from 3 to 483 W m^-2sr^-1, depending on the DEL characteristics and age-related differences in light transmission to the human eye. Among the tested lamps, Luna showed the lowest blue light radiance (L(λ)) (0.09 ± 0.05 W m^-2sr^-1), resulting in the longest safe exposure time (t_max) of 38-96 h. In contrast, SKEMA 6 exhibited the highestL(λ) (4.75 ± 3.41 W m^-2sr^-1), leading to the shortestt_max(0.5-2 h). Appropriate DEL use is crucial for minimising direct blue light exposure, and patient eye protection is recommended for prolonged procedures. Indirect exposure remains within safety limits. Future research should focus on optimising DEL design for safety and performance.