Blue light from devices such as smartphones and computers can cause irreversible damage to the eyes, a study in the United States has found.
The study, which was published in July by researchers from the University of Toledo (UT) in Ohio, found that blue light from digital devices could cause diseases such as loss of central vision and night blindness.
One of the researchers of the project, Dr Ajith Karunarathne, told the UT website that humans are continuously exposed to blue light because the eye's cornea and lens cannot block or reflect it.
"It's no secret that blue light harms our vision by damaging the eye's retina," she said.
"Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop."
The study was published in Scientific Reports, an open access journal from the publishers of Nature. Articles in Scientific Reports are free to access, download, share and re-use. Nature is a science journal that was first published in 1869.
Blue light has a very short wavelength relative to other visible lights, so it produces a higher amount of energy.
Exposure to blue light causes a particular molecule in the eye to produce poisonous chemical molecules that affect light-sensitive cells, said the UT researchers.
This can lead to diseases such as age-related macular degeneration (AMD) and night blindness.
AMD is a irreversible medical condition that results in loss of central vision, and is also a major cause of blindness for those above 50 years old, according to the Singapore National Eye Centre website.
Patients can still have enough peripheral vision to continue with some daily activities, but will have difficulty recognising faces, driving, or reading.
The UT researchers are currently measuring light coming from televisions, handphones and table screens to better understand how cells in the eyes respond to everyday blue light exposure.
They added that people who want to protect their eyes from blue light can avoid looking at cell phones or tablets in the dark, and wear sunglasses that can filter both ultraviolet and blue light.
Correction note: This article has been edited for clarity.