Health Hazards of LED Illumination

Visible light in the blue and violet spectral range poses a hazard to the eye, especially the retina. In a joint research project the Ulm University of Applied Science, the University Eye Hospital Frankfurt, Pharmpur, Königsbrunn, and Epigap Optronic, Berlin, are working on new, patient-friendly miniature LED illumination systems for vitreoretinal surgery, with reduced short wave-length emission and limited maximum exposure doses.

Photograph of different white LEDs – their emission spectra allow the comparative evaluation of potential health hazards. (Source: M. Hessling, HS Ulm)

In a further study the researchers also investigated the potential health effect of the increasing use of white LEDs for domestic and office lighting, which are feared not only to pose a thread to the retina but are also assumed to influence the melatonin-driven human day-night rhythm with cancer and psychological effects as potential consequences.

In this study the spectra of typical commercial representatives of illuminants (cold and warm white LED, fluorescent lamp, halogen lamps and a tablet display) were measured, and compared to each other and to a typical sun light spectrum at noon with respect to the danger to the retina and the melatonin inhibition.

The result is that LED illuminants do not pose an increased health hazard in general. Cold white LEDs are a higher burden for the eye and the day-night rhythm as halogen lamps, but there is no illuminant as good in these respects as warm white LEDs. And even the stress caused by cold white LEDs is still somewhere between that of a fluorescent lamp and sun light at noon. Therefore, the increasing application of LEDs should be no significant additional burden, when compared to conventional illuminants and sun light.

Spectral comparison of different white LEDs that differ substantially in the blue regime. (Source: M. Hessling, HS Ulm)

The researches also suggested the introduction of a consumer label for the potential health effect of illuminants, similar to the so-called EU energy consumption labels, in which lamps are classified in A, B, C, … . In the simplest form, all illuminants with low blue light emissions comparable or below halogen lamps could receive a “blue light label of approval”. (Source: M. Hessling, HS Ulm)

Reference: M. Hessling et al.: LED Illumination – A Hazard to the Eye?, Optik Photonik 13(4), November 2018; DOI: 10.1002/opph.201800029

Links: Institute of Medical Engineering and Mechatronics (M. Hessling), Dept. Mechatronics and Medical Engineering, Ulm University of Applied Science, Ulm, GermanyKlinik Augenheilkunde, Klinikum der Johann-Wolfgang-Goethe-Universität Frankfurt am Main, GermanyPharmpur GmbH, Königsbrunn, GermanyEPIGAP Optronic GmbH, Berlin, Germany

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