A review of 17 randomized controlled trials in the Cochrane Database of Systematic Reviews confirms what eye care experts have long said about popular glasses.
“There is no evidence that blue-light blocking glasses provide health benefits, or even be beneficial for your eyes.” Rahul Khuranaa vitreoretinal surgeon and spokesperson for the American Academy of Ophthalmology, was not involved in the study.
glasses company such as warby hoodie and Felix Gray We appeal to consumers the possibilities of eyeglasses. Warby Parker’s website states, “If screen time is affecting your sleep, blue light blocking lenses may help.” Felix Gray says on his webpage that wearing blue light blocking glasses can reduce symptoms such as eye strain, dry eyes and eye strain. The companies did not respond to emailed requests for comment.
Some manufacturers of prescription glasses may charge an additional fee (up to $50) for lenses that contain blue light blocking.
Blue light lenses and eye strain
Downey said blue light is part of the visible light spectrum and has relatively short wavelengths. We are exposed to blue light from digital devices and, at an even higher level, blue light from the sun.
Some eyewear companies claim that the blue light emitted by screens causes eye strain. American Academy of Ophthalmology Blue light does not cause eye fatigue, damage the retina, or cause diseases such as macular degeneration. The association said studies of blue light, which shows cell damage, were done with cells and animals in dishes. The study said in an article that the experiment “did not mimic the natural exposure of a living human eye to blue light, nor did it use blue light from a computer screen.”
Khurana said staring at screens for long periods of time can cause eye strain.
“Normally, your eyelids blink 15 times a minute,” he said. “But when he’s focused on something, like looking at a screen or looking at a computer, his blink reflex drops to five or seven times a minute, resulting in dry eyes. Masu.”
Symptoms of eye strain include eyestrain, burning or pain, and even blurred vision, Downey said.
Three of the 17 trials included in the review evaluated blue-light reflecting lenses and eye fatigue. The common outcome measure was the subjective visual fatigue score. All three trials, with a total of 166 participants, found that visual fatigue was associated with wearing lenses that filtered blue light versus those that did not filter blue light. No significant differences were reported.
He said the investigation showed “predictable results.” Kevin M. MillerProfessor of Clinical Ophthalmology at the University of California, Los Angeles, but was not involved in the study.
“When an optician tries to convince you about blue blockers, say ‘I don’t think so,'” he said. “That will be my answer.”
Blue light lenses and sleep quality
Our brains have internal clocks known as circadian rhythms that regulate things like sleep. Light and dark can affect this rhythm. Short-wave light, such as blue light, is preferentially absorbed by photoreceptor cells in the retina, which most affect the body clock. Light also suppresses melatonin, the hormone that signals darkness.
For example, bright light from your device at night, especially short wavelength light, can disrupt your body clock, making it difficult to fall asleep and stay asleep.
The idea behind blue block lenses is to block light from entering your eyes and disrupt your circadian rhythms. But this has not been established with any degree of certainty in clinical studies, Miller said.
This review looked at six studies with a total of 148 participants on the effect of blue light blocking glasses on sleep quality. According to Downey, the findings were inconsistent, with three studies showing significant improvements in sleep scores, and three others showing no significant difference between blue-light-blocking glasses and non-blue-light blocking glasses. reportedly not.
Professor Downey added that patients in the study had sleep and mood disturbances. “They didn’t appreciate interventions against the general population,” she says. “Thus, we can’t say anything about its potential usefulness for sleep in healthy adults in general.”
Blue light lenses and other effects
The review also found that blue light-blocking lenses had “little or no effect” on visual performance and daytime alertness.
“The uncertainty in these effects is due to the lack of available data and the small number of studies reporting these results,” the authors said in their review.
According to Downey, the researchers found no difference in the effects of blue-cut lenses on contrast sensitivity, color vision, and what the authors call “unpleasant glare,” a phenomenon that causes eye discomfort from bright light sources. He said he tried to find out if there were any.
These results were not reported in any study, so researchers couldn’t draw conclusions about the impact of blue-blocking lenses on back-of-the-eye health, Downey said.
Possible treatments for eye strain
Experts say there are other things you can consider besides buying blue-light-blocking glasses.
- Use the “20-20” rule. For every 20 minutes you spend staring at a screen, look at an object 20 feet away for 20 seconds, says Khurana.
- Sit at arm’s length from your computer screen.
- If you wear contact lenses and your eyes feel dry, put on your regular prescription glasses and take a break.
- Use glasses with proper prescription. “Because any deviation in the prescription causes eye strain more than anything else,” says Miller. “People should wear glasses that are appropriate for their typical distance from the screen when they are seated.”
If eye strain persists, see an eye health care professional who can perform a thorough eye health check, Downey says. “Some eye strain can actually be caused by eye health or vision problems,” she says.