Photobiological safety

Photobiological safety refers to the assessment of potential hazards to the eyes and skin posed by optical radiation from artificial light sources. Depending on the wavelength, intensity and duration of exposure, different biological effects may occur.

In the case of visible light sources, the potential for photochemical damage to the retina caused by short-wavelength visible radiation is particularly relevant. This is referred to as blue light hazard or Blue Light Hazard.

The risk of a blue light hazard depends in particular on several factors:

1. the luminance of the light source,
2. the duration of exposure, and
3. the spectral composition of the light, in particular the proportion of short-wavelength visible radiation

Risk assessment

Modern LEDs can achieve high luminance due to their small light-emitting area. In the case of white LEDs, there may also be a pronounced short-wavelength component within the visible spectrum. Depending on their design, power and application, an assessment of photobiological safety may therefore be required.

An important basis for this assessment is EN 62471 ‘Photobiological safety of lamps and lamp systems’. IEC/TR 62778 contains supplementary procedures and criteria for assessing the blue light hazard posed by visible light sources.