CIE Position Statement on the Blue Light Hazard
April, 2019
There have been a number of reports in the media about the risk to human health following
exposure to light from sources such as light emitting diodes (LEDs), referring to the term “bluelight hazard” (BLH). This term has been inaccurately used to represent the risk of actual eye
damage and the influence on general well-being.
The term “blue light hazard” should only be used when considering the photochemical risk tothe retinal tissues of the eye (technically referred to as “photomaculopathy”), usuallyassociated with staring into bright sources, such as the sun or welding arcs. “Blue” is includedin the term because the risk of photochemical injury is wavelength-dependent, peaking in theblue part of the optical radiation spectrum around 435 nm to 440 nm. The International
Commission on Non-Ionizing Radiation Protection (ICNIRP) have published the “blue lighthazard function”, a wavelength-dependent weighting function, and guideline exposure limits[1]. The CIE has standardized this function as part of the CIE S 009:2002 "Photobiologicalsafety of lamps and lamp systems", now published as IEC 62471:2006/CIE S 009:2002 [2].
There is no evidence in humans of any adverse health effects from occasional exposure tooptical radiation at the exposure limits.
Lamps, including LEDs, which emit primarily white light will usually contain a proportion of lightat wavelengths that are relevant to the assessment of the blue light hazard. Lamps that are“cooler”, or attributed to a high colour temperature, are likely to contain a higher proportion ofblue light than sources that are “warmer” or of a lower colour temperature. Indeed the blue lighthazard exposure limit from incandescent and LED lamps for general lighting is similar for
similar colour temperatures. Practical assessments have shown that the blue light hazard
exposure limits are not exceeded under all reasonably foreseeable use conditions.
Furthermore, the exposure levels are often lower than experienced from viewing a blue sky.
It is also important to consider eye exposures in practice [3]. A number of studies have been
published, with associated media coverage, which claim adverse effects from white-lightsources. Most of these studies have unusual conditions, including:•••••long-term exposure,high colour temperature LEDs (i.e. a very high blue component),exposures significantly in excess of the ICNIRP exposure limit,
fixation on the light source,
the use of nocturnal animal models or human cells in vitro.

It is fundamental to appreciate that a white-light source emitting blue light at levels sufficient toapproach the blue light hazard exposure limit would be extremely bright, thus producing
discomfort glare, and that to stare into such sources would be considered unusual behaviour.
Also, very high colour temperature lighting is perceived by most people as unpleasant anduncomfortable, particularly for lighting of homes. It is recognized that during normal behaviour,
we experience transient exposures to high light levels, and may get many such exposures perday. However, accumulation of these exposures over the day will not result in the exposure
limits being exceeded.

Whilst the CIE considers that the “blue light hazard” is not an issue for white-light sources usedin general lighting, even for those that are blue-enriched, caution is suggested forcircumstances occurring over many days with continuous exposure to optical radiation, atlevels that approach the blue light hazard exposure limit. Indeed such exposure should beavoided. Such exposure is unlikely for white-light sources, but may be possible with sourcesthat primarily emit blue light.
It should also be recognized that the use of sources emitting primarily blue light are a cause ofconcern for exposure to children’s eyes. Even if the blue light hazard exposure limit is notexceeded, such sources may be dazzlingly bright to youngsters. For this reason, the use ofblue indicator lamps is not recommended for toys and other devices that may be viewed bychildren. Where blue-light sources are used in such products, the blue light hazard exposure
limit should be reduced by a factor of 10. This is even more important for light sources emitting
violet and deep-violet radiation.
There have been claims that exposure to blue light may be linked to the risk of age-related
macular degeneration. Such claims are currently speculative and are not supported by thepeer-reviewed literature.
The term "blue light hazard" should not be used when referring to circadian rhythm disruption
or sleep disturbance. However, the CIE recognizes that there is public concern over the nonvisual influences of blue light on human health and has previously issued a position statementon this [4]. An update on this will be issued in due course taking into account, for example, thenew international standard CIE S 026:2018 [5].

References[1] ICNIRP Guidelines on Limits of exposure to incoherent visible and infrared radiation.
Health Physics. 105(1):74‐96; 2013 (available from www.icnirp.org).
[2] IEC 62471:2006/CIE S 009:2002 Photobiological safety of lamps and lamp systems(bilingual edition) / Sécurité photobiologique des lampes et des appareils utilisant deslampes.
[3] Sliney, D H, Bergman, R and O’Hagan, J. Photobiological Risk Classification of Lampsand Lamp Systems—History and Rationale. LEUKOS, 12:4, 213-234, 2016, DOI:
10.1080/15502724.2016.1145551.
[4] CIE Position Statement on Non-Visual Effects of Light – Recommending Proper Light at
the Proper Time, June 28, 2015 .
[5] CIE S 026/E:2018 CIE System for Metrology of Optical Radiation for ipRGC-Influenced
Responses to Light.

About the CIE and its Position Statements
The International Commission on Illumination – also known as the CIE from its French title, theCommission Internationale de l´Eclairage – is devoted to worldwide cooperation and theexchange of information on all matters relating to the science and art of light and lighting, colourand vision, photobiology and image technology.
With strong technical, scientific and cultural foundations, the CIE is an independent, non-profit
organization that serves member countries on a voluntary basis. Since its inception in 1913, it
has been accepted as representing the best authority on the subject matter of its scope. As
such the CIE is recognized by ISO as an international standardization body, publishing global
standards on the fundamentals of light and lighting.
CIE position statements are approved by the CIE Board of Administration, which includes theDirectors of all the CIE Divisions (the bodies that carry out the scientific work of the CIE), after
first ensuring agreement with the relevant CIE Technical Committees.
For any further information please contact
CIE Central BureauKathryn Nield, General Secretary
Babenbergerstraße 9/9A, A-1010 Vienna, Austria
Phone: +43 1 714 31 87
Email: kathryn.nield@cie.co.at
Website: http:/www.cie.co.at