Does blue light from screens cause eye strain?

The short answer

The American Academy of Ophthalmology (AAO) says there is no scientific evidence that blue light from digital devices damages the eye, and that the sun is a far bigger source of blue light than any screen. It puts screen discomfort down to digital eye strain, which it says comes from how people use their screens, not from anything coming out of them.

The 2023 TFOS report on the digital environment agrees on the causes: mainly blinking less and less fully, an uncorrected prescription, the demand of the task, and the screen’s position, brightness and glare. Blue light isn’t among them.

What the reviews found

The 2023 Cochrane review (Singh and colleagues) looked at 17 randomised trials of blue-light filtering glasses against ordinary clear lenses. The trials were small, from 5 to 156 people, and short, from under a day to five weeks. The glasses may make no difference to eye strain over less than a week (low-certainty evidence), probably make little or no difference to sharpness of vision, and no trial looked at the health of the retina. A few trials reported side effects, infrequent but including headache, discomfort and lower mood.

The College of Optometrists, the UK’s professional body for optometrists, says the best evidence available doesn’t support blue-blocking lenses for the general population, whether to improve vision, ease eye fatigue, improve sleep or protect the macula, and that the Cochrane review is consistent with its own earlier review. The AAO doesn’t recommend them either, and the TFOS report found blue-light blocking doesn’t appear to be an effective way to manage digital eye strain.

What the evidence doesn’t show: the trials are short, so effects over months or years are unknown, and none was designed to test long-term harm from screens.

Blue light and sleep

Sleep is a separate question. The AAO says blue light does affect the body’s circadian rhythm: it is alerting during the day, and screen use late in the evening can make it harder to fall asleep. It suggests cutting screen time in the hours before bed and using your device’s night settings.

Whether filtering glasses help sleep is unclear. In the Cochrane review, six trials with 148 people measured sleep: three found better sleep scores with the glasses and three found no difference, and the evidence was rated very low certainty.

What helps instead

Aim at the causes that are known. Blink fully and more often, especially during focused work, when blinking drops. Take short breaks to look into the distance. Set the screen about an arm’s length away, a little below eye level, and cut glare from windows and lights. And get your eyes tested: TFOS advises a full correction of your prescription for the distances you work at.