Screens

Do children need blue light glasses?

The coating offered at the optical shop counter has never been tested in a child. Here is what the adult research found, and what is really making your child's eyes sore after an hour on a screen.

by Dr Chan Li Yen · MBBS, MOphth (UM), Fellowship in Paediatric Ophthalmology & Strabismus

Practises at Hospital Kuala Lumpur 11 min read · 2,046 words

Key takeaways

There is no randomised evidence at all for blue light filtering lenses in children: every trial in the largest review was done in adults.
In adults, the review found the lenses may make no difference to eye fatigue, probably make no difference to how sharply a person sees, and gave an indeterminate picture for sleep.
A national optometry body states plainly that the evidence does not support these lenses for visual performance, eye fatigue, sleep or macular health, and tells its members to say so.
Sore eyes after a screen are usually dryness: children's blink rate more than halves within the first minute of gaming and stays down for an hour.
Breaks, distance, a lit room and time limits address that. A filter on a lens cannot make a child blink.

It usually happens at the counter, after the prescription is settled and everyone has agreed on the frame. Would you like to add the blue light coating? It is not much more. And the parent, who has just been told their seven year old needs glasses and is already feeling responsible for the iPad, says yes, because saying no feels like refusing to protect your child.

So let me answer the question the way I would if you rang me from that counter. There is no evidence that a child needs blue light filtering lenses. That is not a fashionable opinion, and it is not me being sniffy about optical shops. It is what the research says, and the most striking thing about that research is what is missing from it.

Do blue light glasses actually do anything for a child?

No trial has ever been done to find out. The largest review of blue light filtering spectacle lenses gathered every randomised trial it could find, and every single one was in adults. There is no paediatric evidence in it at all. Not a negative trial in children, not a disappointing trial in children: no trial in children.

That matters more than another round of argument about the adult findings, because a shop assistant offering the coating for a child's glasses is offering something that has never been tested in a child. When I say I cannot recommend it, that is the reason. I am not weighing a small benefit against a cost. I am looking at an empty column.

What did the adult research actually find?

Very little, and not confidently. The review included 17 randomised trials, with as few as five and as many as 156 people in each, and follow-up periods running from less than one day to five weeks. Not one of those trials had a low risk of bias across all seven categories the reviewers checked. The studies were so different from each other, and reported so little usable data, that the reviewers could not combine the results at all.

What they could say, they said carefully. There may be no difference in eye fatigue scores with blue light filtering lenses compared with ordinary ones, on follow-up shorter than a week, and they rated that finding low certainty. There is probably little or no effect on how sharply a person sees. On sleep, the trials pointed in different directions and the review called the picture indeterminate, which is a genuine "we do not know" rather than a polite no. And on the health of the macula, the part of the retina that does your fine central vision, there was no randomised evidence at all.

Every trial was in adults, and the reviewers could not pool a single outcome.

A national professional body for optometrists puts it more bluntly than a review is allowed to. Its position statement says the best scientific evidence currently available does not support using blue blocking lenses in the general population to improve visual performance, relieve eye fatigue or visual discomfort, improve sleep quality or protect the macula. It goes further and tells optometrists who sell these lenses to make patients aware of exactly that. If the profession selling them is being told to say there is no strong evidence, a parent at a counter is entitled to hear it too.

If it is not blue light, why do my son's eyes hurt after gaming?

Because he has almost stopped blinking, and that has been measured. In a study of 36 children aged 6 to 15 playing on a smartphone, blink rate fell from about 21 blinks a minute to about 9 within the first minute of the game starting, and stayed there for the whole hour. The gap between blinks stretched from roughly three seconds to nearly nine. Their dry eye symptoms got worse across that hour.

Read that again, because it is the whole article. Within one minute. Not after an hour of accumulated strain, not because of a wavelength of light, but because a child locked into a game forgets to do the thing that spreads tears across the front of the eye. Sore, gritty, red, watery, light-sensitive, blurry at the end of a session: those are dry eye symptoms, and they are what most parents are actually describing when they ask me about blue light.

A filter on a lens does not make anyone blink. That is why a coating cannot fix this, and why a break can.

What should I do instead?

Interrupt the staring, and make the interruption something that happens rather than something you announce. The habit of looking up from a screen every twenty minutes exists precisely because blinking and focusing both recover when the eyes leave the screen. In practice, in my clinic, what works is structural rather than motivational: the game gets paused for a drink, the tablet lives somewhere with a door, homework happens at a table rather than lying down with a phone held a hand's width from the face.

Two smaller things help alongside the breaks. Put distance between the screen and the face, arm's length rather than resting on a chest. Keep the room lit, rather than letting a bright screen be the only light in a dark bedroom. If a child's lids are also crusty or sticky in the mornings, the standard advice is a warm flannel pressed gently on the closed lids, then a gentle wipe with cotton wool soaked in warm water, and it helps a surprising number of children. If a few weeks of all that changes nothing, that is the point to have the eyes looked at rather than to buy a different lens.

Is the blue light from a tablet damaging his retina?

I cannot tell you it is, and I cannot tell you a filter would protect him if it were. Those are two separate gaps and both are real. The review found no randomised evidence whatsoever about blue light filtering lenses and macular health, and the optometry position statement says openly that it is unclear whether these lenses preserve macular health or change the risk of macular degeneration later in life. Nobody has measured it in a trial.

What I can tell you is that in years of examining children's retinas, screen use is not what brings a child's macula to my attention. The genuine screen-related worry for a Malaysian child is a different one, and it is about how the eye grows rather than about light: why short-sightedness is rising so fast here is a separate question with a separate and more careful evidence base, and a blue light coating has never been part of that discussion.

Will blue light glasses help her sleep better?

Nobody can honestly tell you yes or no, and I would be wary of anyone who does either. The trials on sleep pointed in different directions, in adults, over follow-up periods measured in days and weeks, and the review's own word for the result was indeterminate. The professional body's reading is firmer: the best evidence available does not support using the lenses to improve sleep quality.

Those two statements are not quite the same, and I am giving you both rather than picking the one that sounds tidier. What is not in dispute is that a device in a bedroom is a device in a bedroom whatever coating is on the child's glasses.

We already bought the coating. Have we wasted our money?

Do not throw them away, and please do not feel foolish. The lens underneath the coating is doing the real work, which is correcting your child's sight, and that part matters enormously. The coating simply has not been shown to do the job parents are told it does.

What I would not want is for the coating to become the reason nobody sets a limit, or the reason a child with sore eyes waits three months before anyone looks at them. If your child is rubbing, blinking hard, complaining of headaches after school or holding things very close, that needs an eye test rather than a lens upgrade. Sitting very close to a screen is a sign worth taking seriously, and it is the sort of thing a filter cannot answer.

Book an eye test rather than a lens upgrade if…

Your child holds books or a screen unusually close, or sits very close to the television.
One eye drifts, turns or closes in bright light, or your child tilts their head to see.
There are headaches after school or homework, or your child loses their place while reading.
Eyes are red and sore for more than a few weeks despite breaks and lid cleaning, or your child rubs constantly.
Any eye becomes painful, very red, or sensitive to light, or your child's sight changes suddenly.

Common questions

The optical shop offered a blue light coating for my son's glasses. Is it worth it?

There is no evidence behind it for a child. The largest review of blue light filtering lenses found no randomised trials in children at all, and in adults it could not show a benefit for eye fatigue or vision. The prescription in that lens is what matters for your child; the coating on top of it has not been shown to do anything.

Does blue light from the iPad damage his eyes?

Nobody has demonstrated that in a trial, and nobody has demonstrated that a filter would protect against it either. The review found no randomised evidence whatsoever on these lenses and the health of the macula, and the optometry position statement says it remains unclear whether they preserve macular health. What is measurable after screen use is dryness, not damage.

Will blue light glasses help her sleep?

Nobody can tell you honestly, and I would be careful of a shop that says yes. The adult trials on sleep pointed in different directions and the review called the result indeterminate. The optometry position statement goes further and says the evidence does not support using the lenses to improve sleep quality.

His eyes hurt after gaming. If it is not blue light, what is it?

Almost always dryness from not blinking. In a study of 36 children aged 6 to 15, blink rate fell from about 21 a minute to about 9 within the first minute of gaming and stayed there for an hour, while dry eye symptoms worsened. Sore, gritty, red or watery eyes at the end of a session fit that picture, and breaks are the treatment.

Is night mode or a screen filter app enough instead?

It is not a substitute for breaks, because the problem is not the colour of the light. A child staring without blinking will still have dry, sore eyes with the warmest screen setting available. Use whatever display setting your child finds comfortable, and set the limits and the breaks separately.

So are blue light glasses a scam?

I would not put it that way, and it is not fair to the optometrist fitting them. The lenses do filter some blue light; what has not been shown is that filtering it helps a person see better, feel better or sleep better. The professional guidance is simply that patients should be told there is no strong evidence, and that is the conversation to have at the counter.

My child already wears them. Should I change the glasses?

No. Keep wearing them, because the prescription underneath is doing real work and interrupting that helps nobody. Just do not count on the coating to solve tired eyes, and do not let it delay an eye test if something else is going on.

Do blue light glasses stop short-sightedness getting worse?

There is no evidence that they do, and the review of these lenses did not even measure it. How fast short-sightedness progresses is a separate question with its own treatments and its own trials, none of which involve a filter coating. If your child's prescription is climbing each year, that deserves its own appointment.

References

Cochrane Database of Systematic Reviews 2023 · Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults · pubmed.ncbi.nlm.nih.gov
The College of Optometrists · Position statement: blue blocking spectacle lenses · www.college-optometrists.org
Contact Lens and Anterior Eye 2022 · Smartphone gaming induces dry eye symptoms and reduces blinking in school-aged children · pmc.ncbi.nlm.nih.gov
NHS · Dry eyes · www.nhs.uk
AAPOS · Excessive blinking in children · www.aapos.org

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.