Document Type : Review Article

Authors

• Masoud Haghani ¹
• Samaneh Abbasi ²
• Leila Abdoli ³
• Seyedeh Fatemeh Shams ³
• Batool Faegheh Baha’addini Baigy Zarandi ⁴
• Nasrin Shokrpour ⁵
• Atefeh Jahromizadeh ³
• Seyed Alireza Mortazavi ⁶
• Seyed Mohammad Javad Mortazavi ⁷

¹ Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

² Department of Medical Physics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

³ Department of Medical Physics and Engineering, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

⁴ Department of Pharmacology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

⁵ School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

⁶ School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

⁷ Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran

Abstract

Research conducted over the years has established that artificial light at night (ALAN), particularly short wavelengths in the blue region (~400–500 nm), can disrupt the circadian rhythm, cause sleep disturbances, and lead to metabolic dysregulation. With the increasing number of people spending considerable amounts of time at home or work staring at digital screens such as smartphones, tablets, and laptops, the negative impacts of blue light are becoming more apparent. While blue wavelengths during the day can enhance attention and reaction times, they are disruptive at night and are associated with a wide range of health problems such as poor sleep quality, mental health problems, and increased risk of some cancers. The growing global concern over the detrimental effects of ALAN on human health is supported by epidemiological and experimental studies, which suggest that exposure to ALAN is associated with disorders like type 2 diabetes, obesity, and increased risk of breast and prostate cancer. Moreover, several studies have reported a connection between ALAN, night-shift work, reduced cognitive performance, and a higher likelihood of human errors. The purpose of this paper is to review the biological impacts of blue light exposure on human cognitive functions and vision quality. Additionally, studies indicating a potential link between exposure to blue light from digital screens and increased risk of breast cancer are also reviewed. However, more research is needed to fully comprehend the relationship between blue light exposure and adverse health effects, such as the risk of breast cancer.

Keywords

• Light
• Smartphone
• Circadian Clocks
• Blue Light
• Cognitive Functions
• Vision Quality