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.
â 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 |
â 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 |
â 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 |
â 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 â 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, |
â 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 |
â 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 â The healthy building |
| Author: | International WELL Building Institute (IWBI) |
| Date: | 7. September 2023 |
â 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 |
â 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 |
â 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 |
â 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 |
â 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 |
â 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 âEffects of Light on Humansâ at the DIN Standardization Committee for Lighting Technology (FNL) |
| Date: | 10. September 2025 |
â Overall health
A South Korean study confirmed the positive effects of natural daylight on the length of patient hospitalization.
| Title: |
The Effects of Natural Daylight on Length of Hospital Stay |
| Author: | Man Young Park, Choul-Gyun Chai, Hae-Kyung Lee, Hani Moon, Jai Sung Noh Korea Institute of Oriental Medicine, Architectural Environment Research Institute, Kwangwoon University, Seoul, Korea, Ajou University, Suwon, Korea |
| Date: | 14. September 2025 |
â Eyes
Experimental research conducted by Chinaâs 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 |
â Productivity
A US study has shown that adjusting the amount of daylight and view improves the performance of office workers.
| Title: |
Windows and Offices: A Study of Office Worker Performance and the Indoor Environment |
| Author: | Lisa Heschong California Energy Commission |
| Date: | 20. October 2003 |
â Mood
A study by a team of Swiss, Japanese and Georgian researchers has shown that LED lighting with high melanopic efficiency and a spectral profile mimicking that of the sun improves visual comfort, mood, alertness and sleep compared to conventional LED lighting.
| Title: |
Effect of LED daylight on visual comfort, melatonin, mood, waking performance and sleep |
| Author: | C Cajochen PhD, M Freyburger PhD, T Basishvili PhD, C Garbazza MD, F Rudzik MS, C Renz FND, K Kobayashi MS, Y Shirakawa MS, O Stefani PhD, and J Weibel MS Psychiatric Hospital of the University of Basel, Switzerland Ilia State University, Tbilisi, Georgia Development and Engineering Department, Yokohama-City, Japan |
| Date: | 11. January 2019 |
â Overall health
A UK university study has confirmed that photobiomodulation with 670 nm red light reduces fluctuations in blood glucose levels (glycaemia). Photobiomodulation light therapy thus serves as an effective preventive measure against the development of diabetes.
| Title: |
Light stimulation of mitochondria reduces blood glucose levels |
| Author: | Michael B. Powner, Glen Jeffery Department of Optometry and Visual Science, Centre for Applied Vision Research, School of Health and Psychological Sciences, City, University of London, London, UK Department of Visual Neuroscience, UCL Institute of Ophthalmology, University College London, London, UK |
| Date: | 21. January 2024 |
â Mood
A summary of several scientific papers describes how dopamine, a neurotransmitter associated with the regulation of mood and motivation, is linked to the functioning of circadian rhythms that are influenced by light exposure. Disrupting these rhythms with inappropriate lighting can also negatively affect mood.
| Title: |
Dopamine and its role in circadian rhythm, or is it the other way around? |
| Author: | Mgr. Tereza Ulrichová, Spectrasol |
| Date: | 22. April 2024 |
â Eyes
A study by Beijing University showed that light sources with full spectral composition caused significantly less damage to the retina and photoreceptors compared to conventional LEDs.
| Title: |
More light components and less light damage on ratsâ eyes: evidence for the photobiomodulation and spectral opponency |
| Author: | Jingxin Nie, Ningda Xu, Zhizhong Chen, Lvzhen Huang, Fei Jiao, Yiyong Chen, Zuojian Pan, Chuhan Deng, Haodong Zhang, Boyan Dong, Jiarui Li, Tianchang Tao, Xiangning Kang, Weihua Chen, Qi Wang, Yuzhen Tong, Mingwei Zhao, Guoyi Zhang, Bo Shen Peking University |
| Date: | 7. December 2022 |
â Sleep
University of Texas analysis of existing research demonstrates that sleep and circadian dysfunction associated with unnatural light exposure significantly contribute to the development of a number of psychiatric disorders
| Title: |
The sleep-circadian interface: a window into mental disorders |
| Author: | N. Meyer, R. Lok, C. Schmidt, S. D. Kyle, C. McClung, C. Cajochen, F.A.J.L. Scheer, M.W. Jones, S.L. Chellappa The University of Texas Southwestern Medical Center, Dallas |
| Date: | 23. February 2024 |
â Sleep
Work by a University of Oregon research team describes sleep disturbances in high school students due to lack of quality light in classrooms.
| Title: |
Promoting adolescent sleep and circadian function: A narrative review on the importance of daylight access in schools |
| Author: | Sojeong Kim & Melynda D. Casement Department of Psychology, University of Oregon, Eugene, Oregon, USA |
| Date: | 14. April 2024 |
â Mood
A study by a Dutch university has confirmed the effect of light on mental health, well-being and vitality, as well as on stress.
| Title: |
Salutogenic Effects of the Environment: Review of Health Protective Effects of Nature and Daylight |
| Author: | Femke Beute and Yvonne A.W. de Kort Eindhoven University of Technology, The Netherlands |
| Date: | 21. November 2013 |
â Overall health
Disruption of circadian rhythms has been identified by the World Health Organization (WHO) as an independent risk factor for cancer. A paper by American scientists outlines the main regulatory functions of the circadian rhythm and its relevance to the development and treatment of cancer.
| Title: |
Cancer and the Circadian Clock |
| Author: | Ayesha A. Shafi, Karen E. Knudsen Thomas Jefferson University, Philadelphia, Pennsylvania |
| Date: | 1. August 2019 |
â 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 Georgeâs 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 |
â 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 â 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 |
â 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 Studentsâ and Workersâ Health and Alertness |
| Author: | N. Shishegar, M. Boubekri Illinois School of Architecture, University of Illinois at Urbana-Champaign, USA |
| Date: | 15. April 2016 |
â 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 ZióÅkowska, Bogdan Lewczuk, Natalia SzyryÅska, 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 |
â Eyes
Research conducted by Chinaâs 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 |
â Eyes
A Spanish research has demonstrated negative effects of blue light on the retinal cells of the human eye. In contrast, red light had a regenerative effect on cells damaged by blue light.
| Title: |
Blue light negatively affects the survival of ARPE19 cells through an action on their mitochondria and blunted by red light |
| Author: | Claudia Nunez-Alvarez, Carlota Suárez-Barrio, Susana del Olmo Aguado and Neville N. Osborne Ophthalmological Research Foundation, Oviedo, Asturias, Spain |
| Date: | 9. September 2018 |
â 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 |
