White LED compared with other light sources: age-dependent photobiological effects and parameters for evaluation

Abstract

Ergonomic science at work and living places should appraise human factors concerning the photobiological effects of lighting. Thorough knowledge on this subject has been gained in the past; however, few attempts have been made to propose suitable evaluation parameters. The blue light hazard and its influence on melatonin secretion in age-dependent observers is considered in this paper and parameters for its evaluation are proposed. New parameters were applied to analyse the effects of white light-emitting diode (LED) light sources and to compare them with the currently applied light sources. The photobiological effects of light sources with the same illuminance but different spectral power distribution were determined for healthy 4–76-year-old observers. The suitability of new parameters is discussed. Correlated colour temperature, the only parameter currently used to assess photobiological effects, is evaluated and compared to new parameters.

Keywords:

• general lighting
• LED
• photobiological effects
• blue light hazard
• melatonin production
• correlated colour temperature (CCT)
• melatonin suppression time

Funding

Marta Klanjšek Gunde and Grega Bizjak acknowledge financial support from the state budget by the Slovenian Research Agency (program No. P1-0030 and P2-0356, respectively).

Disclosure statement

No potential conflict of interest was reported by the authors.