Progress in Retinal and Eye Research 30 (2011) 239e257 Contents lists available at ScienceDirect Progress in Retinal and Eye Research journal homepage: www.elsevier.com/locate/prer Light-emitting diodes (LED) for domestic lighting: Any risks for the eye? F. Behar-Cohen a,b,c,*, C. Martinsons d, F. Viénot e, G. Zissis f, A. Barlier-Salsi g, J.P. Cesarini h, O. Enouf i, M. Garcia d, S. Picaud j,k, D. Attia h a Inserm UMRS 872, Physiopathology of Ocular Diseases: Therapeutic Innovations, Centre de Recherche des Cordeliers, 15 rue de l’Ecole de Médecine, 75006 Paris, France b Université Paris Descartes, France c Assistance publique-Hôpitaux de Paris, Hôtel-Dieu de Paris, Department of Ophthalmology. 1, Place du Parvis Notre Dame, 75006 Paris, France d Centre Scientifique et Technique du Bâtiment (CSTB), 24 rue Joseph Fourier e 38400 St Martin d’Hères e France and 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France e Centre de Recherches sur la Conservation des Collections, CNRS USR 3224 e Muséum National d’Histoire Naturelle, Paris, France f LAPLACE, Université Toulouse III, 118 Route de Narbonne, 31062 Toulouse cedex 9, France g Institut National de Recherche et de Sécurité (INRS), Rue du Morvan CS 60027, 54519 VANDOEUVRE Cedex, France h French agency for food, environmental and occupationnal health & safety (ANSES), Maisons-Alfort, France i Laboratoire National de Métrologie et d’Essais (LNE), 29, Avenue Roger Hennequin, 78197 Trappes, France j INSERM, U968, Institut de la Vision, Paris, UPMC Paris 06, UMR_S968,CNRS, UMR 7210, Institut de la Vision, CHNO des Quinze-Vingts, 17 rue Moreau, Paris F-75012, France k Fondation Ophtalmologique Adolphe de Rothschild, Paris, France article info abstract Article history: Light-emitting diodes (LEDs) are taking an increasing place in the market of domestic lighting because Available online 14 May 2011 they produce light with low energy consumption. In the EU, by 2016, no traditional incandescent light sources will be available and LEDs may become the major domestic light sources. Due to specific spectral Keywords: and energetic characteristics of white LEDs as compared to other domestic light sources, some concerns LEDs have been raised regarding their safety for human health and particularly potential harmful risks for the Light-toxicity eye. To conduct a health risk assessment on systems using LEDs, the French Agency for Food, Environ- Blue light mental and Occupational Health & Safety (ANSES), a public body reporting to the French Ministers for Retina ecology, for health and for employment, has organized a task group. This group consisted physicists, lighting and metrology specialists, retinal biologist and ophthalmologist who have worked together for a year. Part of this work has comprised the evaluation of group risks of different white LEDs commer- cialized on the French market, according to the standards and found that some of these lights belonged to the group risk 1 or 2. This paper gives a comprehensive analysis of the potential risks of white LEDs, taking into account pre- clinical knowledge as well as epidemiologic studies and reports the French Agency’s recommendations to avoid potential retinal hazards. Ó 2011 Published by Elsevier Ltd. Contents 1. Introduction . .................................................257 2. Light-emitting diodes, LEDs . .................................................257 2.1. Some physics and optics . .......................257 2.2. LED technology . .......................258 3. Interactions of light with biologic systems: mechanisms of light-induced damages . .................... 258 4. Light and the human eye: how does light reaches the retina . ................................... 260 4.1. Thecornea........................................................................................... .......................260 4.2. Theiris .............................................................................................. .......................260 * Corresponding author. Inserm UMRS 872, Physiopathology of Ocular Diseases: Therapeutic Innovations, Centre de Recherche des Cordeliers, 15 rue de l’Ecole de Médecine, 75006 Paris, France. Tel.: þ331 40 46 78 40; fax: þ331 40 46 78 55. E-mail addresses: [email protected] (F. Behar-Cohen), [email protected] (C. Martinsons), [email protected] (F. Viénot), georges.zissis@ laplace.univ-tlse.fr (G. Zissis), [email protected] (A. Barlier-Salsi), [email protected] (J.P. Cesarini), [email protected] (O. Enouf), [email protected] (S. Picaud). 1350-9462/$ e see front matter Ó 2011 Published by Elsevier Ltd. doi:10.1016/j.preteyeres.2011.04.002 240 F. Behar-Cohen et al. / Progress in Retinal and Eye Research 30 (2011) 239e257 4.3. The lens . ..................................................261 4.4. The retina . ..................................................261 4.4.1. Macular pigments . .......................................263 4.4.2. Lipofuscin . .......................................263 5. Retinal control of circadian cycle and pupillary reflex . .................... 264 6. Light and retinal pathology . .................... 264 6.1. Sunlight and retinal pathology . .......................................264 6.1.1. Acute exposure: solar retinitis . .......................................264 6.1.2. Chronic exposure: a link with age-related macular degeneration? . ...........................264 6.1.3. Blue light and glaucoma or other optic neuropathy . ...........................265 7. Artificial light and ocular pathology . .................... 265 7.1. Ophthalmologic instruments . .......................................265 7.2. Welder exposure . ..................................................265 8. Sunlight and artificial light: how to compare potential dangers? . .................... 265 8.1. Comparison of natural and artificial illumination in terms of photometric quantities . ......................265 8.2. Comparison of the spectral power distribution of natural and artificial lights . ..........................266 8.3. State of adaptation of the retina, luminance threshold and glare . ...........................266 9. LED blue-light hazard risk assessment . .................... 266 9.1. Methodology . ..................................................267 9.1.1. Assessment results with single-die high-brightness white LEDs and blue LEDs . ......................269 9.1.2. Assessment results with a multiple-die LED . ...........................271 9.1.3. LED arrays . .......................................271 9.1.4. Single-die LED associated with an optical collimator . ...........................271 9.1.5. Results of blue-light risk assessment carried out on lamps and luminaires . ......................272 10. Anses opinion . .. .....................272 10.1. Photochemical risks of LEDs . .......................................272 10.1.1. Compliance with standards concerning glare . ...........................272 10.2. Anses recommendations . .......................................272 10.3. Concerning use, information and traceability . ......................................273 11. Conclusions and future directions . .....................273 References . ..................................................273 1. Introduction 2. Light-emitting diodes, LEDs Artificial light sources, essential in the daily life of most of 2.1. Some physics and optics Human being consume around 2650 billion MWh/year, which represents almost 19% of the worldwide electricity production. Light is an electromagnetic radiation visible by the intact adult The European Directive for the eco-design of Energy Using Prod- human eye in the range of 380e780 nm, spanning from violet to red ucts (2005/32/CE) recommends improving the energy perfor- light. Like all radiations, light carries energy, the shorter wave- mances of domestic use products in order to protect the lengths being the most energetic ones. Radiometric quantities environment. Consequently, decision was made to progressively define energy-related parameters of optical radiation (Table 1 suppress the least efficient light sources and replace them by summarizes the definition of terms). Radiance is used to describe either compact fluorescent lamps or by Light-Emitting Diodes the “brightness” of a source, i.e., to quantify the amount of light (LED). By the first of September 2016, no more incandescent lights emitted by a source [in W/(m2 sr)] while irradiance is used to will be available in Europe for domestic lighting, and inorganic or describe the power density on a receiving surface [in W/m2]. organic LEDs could become the next generation light sources. Photometric quantities take into account the visual effect of light Indeed, if white LEDs would replace other light sources, about 270 and therefore indicate light levels that are spectrally weighted by millions of tons of CO2 per year would be saved, representing the standard photometric visibility curve (photopic), which peaks a tremendous ecologic gain and, with the growing improvement at 555 nm for the human eye. such as the luminance (formerly of LED ‘s light efficacy, their energetic and environmental benefits referred to as “brightness”) as perceived by a human “standard will not be disputable. observer”, measured in cd/m2 and the illuminance (the light flux Yet, the potential risks of these new light sources need to be density on a receiving surface) measured in lux (luminance which explored. Due to specific spectral and energetic characteristics of is the ratio