A new study indicates that the light from computer screens, mobile phones and other electronic devices is not damaging to the human eye when exposed at normal levels. The study concluded that the light emanating from natural daylight actually contains higher levels of blue light than the illumination coming from devices.
John O'Hagan, head of the Laser and Optical Radiation Dosimetry Group of Public Health England in Chilton, UK and lead author of the study, stated, "Even under extreme long-term viewing conditions, none of the low-energy light bulbs, computers, tablets and mobile phones we assessed suggested cause for concern for public health."
A safe exposure limit for blue light has been set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) based on the blue light emissions from various electronic devices in O'Hagan's study.
O'Hagan's team determined that the highest amount of blue light was emitted by a white screen, so they measured the emission from such a screen at the highest brightness setting as a standard for their study.
The researchers also compared the blue light emitted from various devices to natural light. They measured the amount of blue light generated by staring at the sky (not directly into the sun) on a sunny summer day as well as during a cloudy winter day.
The amount of blue light generated in the summer was only 10 percent of the ICNIRP safe exposure limit, while the amount on a winter day was just 3 percent. The amount of blue light emitted from the electronic devices tested was actually lower than the findings related to the natural light exposure.
That doesn't mean computer users shouldn't be wary of blue light coming from their devices, however, because that light has been shown to affect sleep cycles in device users. While O'Hagan's study didn't address this issue, a light spectrum researcher warned of the potential disruptions brought by blue light on sleep and the circadian rhythms of nighttime electronic device users.
"Displays like laptops, tablets and phones should not be used for a long time at night because its bright emission suppresses the melatonin," said Meenu Singh from the National Tsing Hua University in Hsinchu, Taiwan. Melatonin is also known as the sleep hormone, and it plays a role in the body's natural sleep-wake cycle.
Singh also cautioned users to adjust the brightness of their screens at that time.
Tech addicts who can't stay away from their devices at nighttime may have some even better options now in the form of various apps that filter out the blue light from their screens. In addition, Apple has just introduced Night Shift mode in its latest OS update, iOS 9.3, which allows owners of Apple devices to filter out blue light as well, ensuring a restful night's sleep.
