Originally Published: 17 AUG 23 19:30 ET

By Sandee LaMotte, CNN

(CNN) — Adding a blue-light filter to your eyeglasses may not ease eye strain from computer work, protect the retina or help with sleep at night, according to a new review of existing research.

“We found there may be no short-term advantages with using blue-light filtering spectacle lenses to reduce visual fatigue associated with computer use,” said senior author Laura Downie in a statement. Downie is an associate professor of optometry and vision sciences and director of the anterior eye, clinical trials and research translation unit at the University of Melbourne in Victoria, Australia.

“It is also currently unclear whether these lenses affect vision quality or sleep-related outcomes, and no conclusions could be drawn about any potential effects on retinal health in the longer term,” Downie said. “People should be aware of these findings when deciding whether to purchase these spectacles.”

In reality, it’s not the blue-light emission from our devices that is causing eye strain for most people, said ophthalmologist Dr. Craig See, a cornea specialist at Cole Eye Institute at the Cleveland Clinic in Ohio.

“Most people have computer vision syndrome, which is related to sitting at a computer screen for a long period of time,” said See, who was not involved in the study.

Symptoms of computer vision syndrome include dry eyes, watery eyes, blurry vision, light sensitivity, burning or itchy eyes, and difficulty concentrating and keeping your eyes open, according to the Cleveland Clinic. Eye strain from presbyopia, which is the gradual loss with age of the ability of the eye to focus on nearby objects, can contribute, as can neck and shoulder pain, See said.

“I don’t typically recommend blue-light filters to my patients,” See said. “There’s no reason to think that blue-light filtering is harmful, other than the cost associated with adding it to your glasses. The takeaway here is that it may not be doing as much as we were hoping.”

Only short-term studies

The report, published Thursday in the Cochrane Database of Systematic Reviews, analyzed data from 17 randomized controlled clinical trials conducted in six countries that lasted from a few days to a few months. The review is part of the nonprofit Cochrane Collaboration, an independent, international network of researchers that uses some of the highest standards in evidence-based research.

The brevity of the clinical trials affected the reviewers’ ability to consider longer-term outcomes, Downie said. “Our certainty in the reported findings should be interpreted in the context of the quality of the available evidence.”

In addition, blue-light filtering lenses only filter between 10% and 25% of blue light from artificial devices such as computer screens, and that blue light is only “a thousandth of what we get from natural daylight,” said first author Dr. Sumeer Singh, a postdoctoral clinical research fellow in the anterior eye, clinical trials and research translation unit at the University of Melbourne.

“Filtering out higher levels of blue light would require the lenses to have an obvious amber tint, which would have a substantial effect on colour perception,” he said in a statement.

The review was conducted to answer an ongoing debate on whether blue-light filtering lenses have any merit in ophthalmic practice, Downie said.

“Research has shown that these lenses are frequently prescribed to patients in many parts of the world, and a range of marketing claims exist about their potential benefits, including that they may reduce eye strain associated with digital device use, improve sleep quality and protect the retina from light-induced damage,” she said.

“Our findings do not support the prescription of blue-light filtering lenses to the general population,” Downie said. “These results are relevant to a broad range of stakeholders, including eye care professionals, patients, researchers and the broader community.”

How to help your eyes

There are a number of actions you can take to ease or prevent eye strain, See said. First, if you haven’t had your eyes checked in the last year or two, visit a specialist right away. Your eyes may have weakened, making a new prescription necessary.

“When you visit the eye doctor, go in with a measurement of how far away your face is from your computer screen, so the doctor can maximize your prescription,” See said. “You should be arm’s length from the screen. And if you’re using a laptop, consider getting a larger external display that you can plug into.”

Having a bigger screen can ease eye strain by increasing text size and may also reduce headaches and neck strain from bending over the laptop, See explained.

“If your text is difficult for you to read, it’s going to take you longer to read it,” he said. “You will be affecting your posture to do so, and you’ll be blinking even less if you’re straining to read things. Having a bigger screen can help with that.”

The eye stops blinking regularly as computer time increases, See said, so taking regular breaks from work at the computer is also important. Try using the 20-20-20 rule — every 20 minutes, look at something 20 feet (6 meters) away for 20 seconds, which can encourage your eyes to blink at their normal rate. Better yet, get up and walk away, because constant sitting will increase neck and back strain.

If dry eyes are part of the problem, a warm compress applied to your eyes can offer relief, as can over-the-counter artificial tears. But keep the use to a minimum – many contain preservatives and should be used no more than four times a day.

“If you need them more often, you need to move to preservative-free tears, which come in a vial,” See said. “I will say if you need artificial teardrops more than four times a day, then I think it’s a good idea to see an eye doctor for your condition.”