Studies
Independent research and documents on the effects of light on humans
We present studies from scientific institutions around the world and results from renowned laboratories and workplaces dealing with the effects of light on the body.
✓ Eyes
A Spanish study in mice investigated the effects of a blue light blocking filter and found that it has a protective effect against photoreceptor and retinal damage caused by exposure to high intensity light.
| Title: |
Removal of the blue component of light significantly decreases retinal damage after high intensity exposure |
| Author: | Javier Vicente-Tejedor, Miguel Marchena, Laura Ramirez, Diego García-Ayuso, Violeta Gómez-Vicente, Celia Sánchez-Ramos, Pedro de la Villa, Francisco Germain Universidad de Alcalá, Universidad Complutense, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria- Hospital Virgen de la Arrixaca, Universidad de Alicante |
| Date: | 15. March 2018 |
✓ Eyes
German study confirms the protective effects of the photobiomodulatory red part of the spectrum (PBM) by slowing the progression of retinal pathologies via mitochondria and energy metabolism
| Title: |
Photobiomodulation Mediates Neuroprotection against Blue Light Induced Retinal Photoreceptor Degeneration |
| Author: | Nora Heinig, Ulrike Schumann, Daniela Calzia, Isabella Panfoli, Marius Ader, Mirko H. H. Schmidt, Richard H. W. Funk, Cora Roehlecke Technische Universität (TU) Dresden, University of Genoa, Center for Regenerative Therapies Dresden (CRTD), German Cancer Consortium (DKTK), German Cancer Research center (DKFZ) |
| Date: | 30. March 2020 |
✓ Eyes
Taiwanese researchers have shown that retinal damage from indoor LED lighting depends on the wavelengths of light and the length of exposure. The damage is mainly related to exposure to light containing short blue wavelengths.
| Title: |
White Light-Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model |
| Author: | Yu-Man Shang,1 Gen-Shuh Wang,1 David Sliney,2 Chang-Hao Yang,3,4 and Li-Ling Lee National Taiwan University, Industrial Technology Research Institute, Hsinchu, Taiwan |
| Date: | 20. December 2013 |
✓ Eyes
Research from a Chinese university has found that LED lighting with a higher colour rendering index (CRI) and a spectral composition close to that of the sun is better for the eyes.
| Title: |
Effect of light-emitting diodes with different color rendering indexes on the ocular tissues of rat |
| Author: | Wen-Yi Chen, Kun-Hong Xiao, Rong Lin, Ze-Ren Qiu, Ya-Min Chen, Ze-Qun Lin, Xiu-Bin Ke, Yan Huang Fujian Medical University, China |
| Date: | 25. January 2022 |
✓ Eyes
In this article, a University of London professor presents the current scientific consensus on light exposure: Blue-violet light is harmful to the human eye, while blue-cyan light is essential for healthy life.
| Title: |
The blue light paradox problem or panacea |
| Author: | John Marshall University College London, UK |
| Date: | 15. February 2017 |
✓ Eyes
US experts have identified blue-violet light (415-455 nm) as phototoxic and stress the need to limit it to protect eyesight, especially at older ages.
| Title: |
Blue light hazard – New Knowledge, New Approaches to Maintaining Ocular Health |
| Author: | Michael E. Boulton, George C. Brainard, William Jones, Paul Karpecki, Ron Melton, Randall Thomas Indiana University School of Medicine, Jefferson Medical College, |
✓ Eyes
A text by a respected neuro-ophthalmologist from Aston University explains how harmful blue light accelerates retinal damage and the development of macular degeneration.
| Title: |
Science behind the danger of blue light to the retina |
| Author: | Prof. Shelby Temple Aston University, Azul Optics |
| Date: | 1. January 2022 |
✓ Eyes
A British study by a London university showed that even short-term exposure to red light around 670 nm significantly improved the ability to see contrasts and colors.
| Title: |
Weeklong improved colour contrasts sensitivity after single 670 nm exposures associated with enhanced mitochondrial function |
| Author: | Harpreet Shinhmar, Chris Hogg, Magella Neveu, Glen Jeffery Institute of Ophthalmology, University College London |
| Date: | 24. November 2021 |
✓ Mood, Overall health
A new advisory document from the International Association of Lighting Designers (IALD) highlights the importance of the biological functions of lighting and recommends its integration into lighting design to support human health and well-being.
| Title: |
Lighting Design for Health, Wellbeing and Quality of Light, A Holistic Approach to Integrative Lighting |
| Author: | International Association of Lighting Designers Kevan Shaw, Ioannis Ladopoulos, Chiara Carucci, Alexia Gkika Lorraine Calcott |
| Date: | 28. February 2025 |
✓ Eyes
New publication by renowned Harvard professor Martin Moore-Ede (The Light Doctor) demonstrates that near-infrared and red light components support human health and regeneration by stimulating mitochondria.
| Title: |
Invisible Healing: Near-Infrared Light and Health, The Light Doctor |
| Author: | Dr. Martin Moore-Ede profesor Harvard Medical School |
| Date: | 25. March 2025 |
✓ Overall health, General health
The document by the Ladenburg Scientific Consortium presented a consensus of top experts in chronobiology, psychology, and neuroscience on the impact of light on biological clocks, sleep, mood, alertness, and overall human health.
| Title: |
Evidence-based public health messaging on the non-visual effects of ocular light exposure: A modified Delphi expert consensus |
| Author: | Manuel Spitschan PhD, Laura Kervezee PhD, Oliver Stefani PhD, Marijke Gordijn PhD, Jennifer A. Veitch PhD, Renske Lok PhD the Ladenburg Light and Health Consortium |
| Date: | 8. May 2025 |
✓ Productivity
Light enriched with a blue component accelerated thinking, improved concentration, and increased perceived alertness in students, as demonstrated by German scientists.
| Title: |
Influence of blue-enriched classroom lighting on students׳ cognitive performance |
| Author: | Oliver Keis, Hannah Helbig, Judith Streb, Katrin Hille ZNL Transfer Center for Neuroscience and Learning, University of Ulm, Germany |
| Date: | 10. September 2025 |
✓ Overall health
In Germany, as of August 2025, the DIN 5031-100 standard became a key guideline for the application and assessment of the non-visual properties and effects of electric light on humans in building interiors.
| Title: |
DIN 5031-100 |
| Author: | Working Committee NA 058-00-27 AA “Effects of Light on Humans” at the DIN Standardization Committee for Lighting Technology (FNL) |
| Date: | 10. September 2025 |
✓ Productivity
Extensive US research has found a significant positive effect of natural daylight on the performance of primary school pupils. The improvement was by 15-26% in math and reading.
| Title: |
Daylighting in Schools – An Investigation into the Relationship Between Daylighting and Human Performance |
| Author: | Lisa Heschong The Pacific Gas and Electric Company, California Board for Energy Efficiency Third Party Program |
| Date: | 20. August 1999 |
✓ Mood
The National Institute of Mental Health of the Czech Republic has confirmed through two years of testing the unique effectiveness of Spectrasol full-spectrum phototherapy devices in the treatment of psychiatric diseases and their positive effect on mood, sleep and cognitive functions.
| Title: |
(1) Technology verification protocol: Light case, |
| Author: | (1) PhDr. Jana Kopřivová, Ph.D., Ing. arch. Lenka Maierová, Ph.D., Mgr. Kateřina Červená, Ph.D., Ing. arch. Hana Kárníková, doc. RNDr. Zdeňka Bendová, Ph.D. (2) PhDr. Jana Kopřivová, Ph.D., Ing. arch. Lenka Maierová, Ph.D., Mgr. Kateřina Červená, Ph.D., Mgr. Katarína Evansová, Mgr. Kateřina Skálová, Bc. Zuzana Kaňková, doc. Ing. Marek Piorecký, Ph.D., Mgr. Přemysl Vlček, Ph.D., Mgr. Karolína Janků, Ph.D., Ing. arch. Hana Kárníková, RNDr. Tereza Nekovářová, Ph.D., doc. RNDr. Zdeňka Bendová, Ph.D. |
| Date: | 15. December 2023 |
✓ Eyes
A study by the Sorbonne University confirmed the harmful effects of concentrated blue and green spectral energy in light, and the ability of the red part of the spectrum to offset these negative effects. It therefore recommends changes to interior lighting standards.
| Title: |
The blue light hazard and its use on the evaluation of photochemical risk for domestic lighting. An in vivo study |
| Author: | Anaïs Françon, Francine Behar-Cohen, Alicia Torriglia Centre de Recherche des Cordeliers, Université Paris Cité, Sorbonne Université |
| Date: | 15. February 2024 |
✓ Overall health
The CIE, the highest global authority on lighting, confirms the need to take into account the biological properties of artificial light for the proper functioning of the human body indoors and emphasises the impact on mental and physical health and vitality
| Title: |
CIE Statement on Non-Visual Effects of Light / CIE Position Statement on Integrative Lighting RECOMMENDING PROPER LIGHT AT THE PROPER TIME 1st, 2nd and 3rd Edition |
| Author: | CIE Central Bureau Dr Peter Zwick |
| Date: | 30. August 2024 |
✓ Mood
Research by the Technical University of Catalonia (Barcelona Tech, UPC) has confirmed that artificial lighting simulating sunlight has positive psychophysiological effects on test subjects in Oslo, Norway, including improved mood and overall well-being.
| Title: |
Influence of Simulated Natural Light on Mood and Well-being Case study at Obos Living Lab, Oslo, Norway |
| Author: | Giovanna Taques Martins, Adrian Muros Alcojor, Maria José Perdomo Centre de Politica de Sol i Valoracions, CPSV / Universitat Politècnica de Catalunya, UPC |
| Date: | 29. May 2023 |
✓ Mood
Exposure to light at night disrupts circadian rhythms that are essential to human health and well-being, while also significantly contributing to the prevalence of mood disorders in modern societies, according to a study by US researchers.
| Title: |
Timing of light exposure affects mood and brain circuits |
| Author: | T. A. Bedrosian, R. J. Nelson Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA, USA Department of Neuroscience, Behavioral Neuroendocrinology Group, The Ohio State University Wexner Medical Center, Columbus, OH, USA |
| Date: | 31. January 2017 |
✓ Mood
A University of Helsinki study found that exposure to bright light increased vitality and reduced depressive states in office workers.
| Title: |
Bright light improves vitality and alleviates distress in healthy people |
| Author: | Timo Partonena, Jouko Lonnqvist Department of Psychiatry, University of Helsinki, Helsinki, Finland |
| Date: | 20. March 1999 |
✓ Sleep
Blue light at bedtime and at night disrupts the sleep cycle by suppressing melatonin release and shifting circadian rhythms, leading to health problems such as increased risk of dementia, diabetes and heart disease.
| Title: |
National Geographic: About sleep and light |
| Author: | Michael Finkel National Geographic |
| Date: | 15. August 2018 |
✓ Sleep
Research from Shanghai’s Fu-tan University investigating the effect of indoor LED lighting has shown that sufficient light with high biological efficiency during the day leads to higher daytime whiteness and night-time sleep quality.
| Title: |
Influence of the spectrum of all-day LED lighting on human daytime and night-time performance |
| Author: | Nuoyi Li, Sicong Zhou, Wenqing Miao, Congshan Dai, Ali Hassan Shah, Yandan Lin School of Information Science and Engineering, Fudan University, Shanghai, China |
| Date: | 15. February 2023 |
✓ Sleep
A paper by the US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) confirms that increasing light exposure at undesirable times and reducing the dynamic range of light between day and night has had negative consequences for human health in relation to melatonin production.
| Title: |
The Complex Effects of Light on Metabolism in Humans |
| Author: | Asuka Ishihara, Amber B. Courville and Kong Y. Chen National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, USA |
| Date: | 14. March 2023 |
✓ Eyes
Experimental research conducted by China’s Tianjin Medical University has shown that prolonged exposure to harmful blue light causes changes on the surface of the eyes that manifest as dry eye syndrome and also increases the risk of eye inflammation.
| Title: |
Influence of Light-Emitting Diode-Derived Blue Light Overexposure on Rat Ocular Surface |
| Author: | Li Nan, Yifan Zhang, Hui Song, Yan Ye, Zhixin Jiang and Shujun Zhao Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Nankai University Affiliated Eye Hospital, Clinical College of Ophthalmology Tianjin Medical University Tianjin Eye Institute, Tianjin, China NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China |
| Date: | 10. January 2023 |
✓ Eyes
Research conducted by China’s Zhejiang University has confirmed that prolonged exposure to harmful blue light significantly damages the retina of the eye, including disrupting mitochondrial function and increasing the risk of macular degeneration.
| Title: |
Long-term blue light exposure impairs mitochondrial dynamics in the retina in light-induced retinal degeneration in vivo and in vitro |
| Author: | Liyin Wang, Xin Yu, Dongyan Zhang, Yingying Wen, Liyue Zhang, Yutong Xia, Jinbo Chen, Chen Xie, Hong Zhu, Jianping Tong, Ye Shen Department of Ophthalmology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China Clinical Research Center, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China Department of Ophthalmology, Shaoxing Central Hospital, Shaoxing, China |
| Date: | 24. January 2023 |
✓ Eyes
A study by Polish and Ukrainian universities confirms that exposure to harmful blue light at even low intensities reduces melanopsin production and damages mitochondria in the inner photosensitive ganglion cells of the retina. Therefore, it is desirable to reduce harmful blue light in long-term light sources, in order to maintain both proper circadian rhythm functions and eye health.
| Title: |
Low-Intensity Blue Light Exposure Reduces Melanopsin Expression in Intrinsically Photosensitive Retinal Ganglion Cells and Damages Mitochondria in Retinal Ganglion Cells in Wistar Rats |
| Author: | Natalia Ziółkowska, Bogdan Lewczuk, Natalia Szyryńska, Aleksandra Rawicka and Alla Vyniarska Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Poland Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Stepan Gzhytskyi National University of Veterinary and Biotechnologies, Ukraine |
| Date: | 23. March 2023 |
✓ Productivity
The prestigious WELL building certification by the global IWBI awards up to 3 points for the application of full-spectrum lighting with circadian effects due to its impact on productivity, well-being and health.
| Title: |
WELL CERTIFICATION – The healthy building |
| Author: | International WELL Building Institute (IWBI) |
| Date: | 7. September 2023 |
✓ Productivity
Team of University of Illinois researchers confirms effects of light on mental function, alertness and health of students and office workers
| Title: |
Natural Light and Productivity: Analyzing the Impacts of Daylighting on Students’ and Workers’ Health and Alertness |
| Author: | N. Shishegar, M. Boubekri Illinois School of Architecture, University of Illinois at Urbana-Champaign, USA |
| Date: | 15. April 2016 |
✓ Mood
Swiss researchers demonstrate the benefits of daylight exposure in the afternoon on alertness, cognitive performance, subjective well-being and mood of office workers
| Title: |
Effects of realistic office daylighting and electric lighting conditions on visual comfort, alertness and mood |
| Author: | A. Borisuit, PhD, F. Linhart, PhD, J. L. Scartezzini, PhD and M. Munch, PhD Solar Energy and Building Physics Laboratory, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland |
| Date: | 21. March 2014 |
✓ Overall health
A paper by a team of Spanish and US scientists summarises the results of research on the influence of circadian rhythms on melatonin production and cardiovascular health.
| Title: |
Melatonin and circadian biology in human cardiovascular disease |
| Author: | Alberto Dominguez-Rodriguez, Pedro Abreu-Gonzalez, Juan J. Sanchez-Sanchez, Juan C. Kaski and Russel J. Reiter Department of Cardiology, Hospital Universitario de Canarias, Tenerife, Spain Department of Physiology, Universidad de La Laguna, Tenerife, Spain Instituto Nacional de Toxicologia Ciencias Forenses, Tenerife, Spain Division of Cardiac and Vascular Sciences, Cardiovascular Biology Research Centre, St George’s University of London, London, UK Department of Cellular and Structural Biology, Health Science Center at San Antonio, The University of Texas, San Antonio, TX, USA |
| Date: | 1. July 2010 |
