Blue-light-filtering glasses — do they really help?

“Protect your eyes from harmful screen light”, “less strain”, “better sleep” — that’s how blue-light-filtering glasses are marketed. Patients often ask whether they’re worth the money. As an optometrist I prefer to answer based on evidence rather than slogans — and for “blue light” the evidence is fairly clear-cut.

Where did the “blue light” filter idea come from?

Screens emit some blue light, which has been linked to hypothetical retinal damage and to sleep disturbance. Hence the idea of “filtering it out”. But it’s worth stating up front: the amount of blue light from a screen is many times smaller than what we naturally receive in daylight.

What does the research say?

Here the evidence is surprisingly consistent:

• Cochrane systematic review (2023) — blue-light-filtering lenses probably do not reduce short-term eye strain from computer use, and their effect on sleep quality and long-term macular health remains uncertain.
• An earlier review (2017) — a lack of high-quality evidence to recommend such glasses for the general population to improve vision, sleep or protect the retina.
• A double-masked randomised controlled trial (2021) — in 120 people with symptoms during computer work, blue-blocking lenses did not change the symptoms or signs of eye strain compared with standard lenses.
• The American Academy of Ophthalmology (AAO) does not recommend special glasses for computer use, noting that strain comes from reduced blinking and near work, not from screen light.

So why do eyes get tired at a screen?

Because the problem isn’t the colour of the light but the way we look: hours of near staring, less frequent and incomplete blinking, and the effort of accommodation and convergence. I describe exactly these mechanisms — and what genuinely helps — in the post Digital eye strain.

And what about sleep?

Using screens in the evening really can make falling asleep harder, but the effect of the filters themselves on sleep remains inconclusive in studies. More effective and cheaper is limiting screens for an hour before bed and dimming the lights in the evening.

What genuinely helps instead of a filter?

• the 20-20-20 rule and regular breaks,
• conscious, complete blinking and lubricating the eyes if they feel dry,
• correct refractive correction (if needed),
• good workstation ergonomics and glare-free lighting.

A blue-light filter isn’t harmful — it just doesn’t, according to the research, do what the adverts promise. The money is better invested in a well-fitted correction and healthy habits.

When are glasses genuinely needed?

Refractive correction is an entirely different matter — if the eyes tire because of uncorrected hyperopia, astigmatism or a binocular-vision problem, the right glasses can make a world of difference. Whether that’s the case for you will only become clear after an examination.

Not sure whether you need glasses for screen work? Write or call — I’ll help you tell the trend from a genuine need.

Sources

1. Singh S, et al. (2023). Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews. PubMed
2. Lawrenson JG, Hull CC, Downie LE. (2017). The effect of blue-light blocking spectacle lenses on visual performance, macular health and the sleep-wake cycle. Ophthalmic & Physiological Optics. PubMed
3. Singh S, Downie LE, Anderson AJ. (2021). Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. American Journal of Ophthalmology. PubMed
4. American Academy of Ophthalmology. Are Blue Light-Blocking Glasses Worth It? aao.org