Don’t buy blue-light glasses to “protect eyesight,” and don’t believe “a few months of screens will ruin your eyes,” but eye pain, swelling, and redness are an emergency

Blue-light lenses show no benefit; skipping them saves a few hundred to over 1000 in mark-up. Compared with ordinary lenses, people who wear them do not differ in how tired the eyes feel or how clearly they see, and no evidence was found that they protect the retina. Screen-related ache and dryness can ease; they do not permanently ruin the eyes. What does ruin eyes is welding arc light, lasers, and an acute glaucoma attack.

Cost

No money, and you save the few hundred to over 1000 yuan mark-up on the lenses.

Benefit

A 2023 Cochrane systematic review included 17 randomized controlled trials, each with 5 to 156 people, followed from under 1 day to 5 weeks. Because data were sparse, the people enrolled differed across trials, and follow-up times did not match, the authors did not pool them into one total. Results below are versus lenses without a blue-light filter. At under one week of follow-up, self-reported eye fatigue “may not differ”; certainty is low. One trial of 120 people had a between-group difference of 9.76 units. The credible range for that difference is 95% CI −33.95 to 53.47. The range crosses positive and negative, so no difference shows. Critical flicker fusion frequency, an objective measure of eye fatigue, “may have almost no difference”; certainty low. Best visual acuity after refractive correction is “probably unaffected.” The difference was 0.00 logMAR (95% CI −0.02 to 0.02). That finding rests on 1 study and 156 people; certainty moderate. Effect on daytime alertness is unclear (2 trials, 42 people, certainty very low). The review also found no evidence supporting protection of the macular retina. An American Academy of Ophthalmology public page states that the claim “long screen time permanently damages the eyes” “is not true”; screens only make the eyes uncomfortable after long use. China’s Classification and Catalogue of Occupational Diseases (2024 edition) lists photic eye injury from welding arcs and laser eye injury as occupational diseases.

Notes

What screens bring is visual fatigue and dry eye — ache, dryness, blur after long looking. Rest and more blinking ease it. It can ease; that is not the same as “ruining the eyes.” That line is from an American Academy of Ophthalmology public page, not a conclusion of the Cochrane review in the sources line, so it counts only as grade C. What can cause irreversible eye injury in a short time is strong light such as welding arcs, ultraviolet, and lasers. Eye injury from welding arcs is called photic keratitis and is a statutory occupational disease. Blocking it needs safety goggles and a face shield, not blue-light lenses — see Section 19, Item 10 (protection from dust, noise, and chemical toxins). Staying up all night staring at a screen: what to watch for is not the screen itself, but one exception. Eye pain and redness with swelling, rainbow rings around lights, plus headache, nausea, and vomiting — that is an acute angle-closure glaucoma attack. It can crush the optic nerve within days; go to an eye emergency the same day — see Section 13, Item 6 (eye emergencies). Dilated pupils in the dark and long head-down posture pushing the lens forward are triggers; high risk is age 50 and above, hyperopia, and a shallow anterior chamber. Dry eye from screens that drags on can also become a chronic condition needing a doctor, not something that vanishes after one night’s sleep. If the eyes stay uncomfortable, or vision is truly falling, see ophthalmology and find the cause; do not just swap lenses on your own. How children and teens prevent myopia is in Section 30, Items 4, 12, and 9 (2 hours outdoors daily, cycloplegic refraction, do not buy “cure myopia” products).

Sources · 3

1. Singh S, Downie LE, Anderson AJ, Keller PR, White SJ, Ang M, Wolffsohn JS (2023). Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database of Systematic Reviews, 8, CD013244. doi.org/10.1002/14651858.CD013244.pub2
2. American Academy of Ophthalmology (2024). Computers, Digital Devices, and Eye Strain（「You may have heard that looking at a computer, smartphone, or other digital screen for long periods of time will permanently damage your eyes. Thankfully, this is not true.」）. aao.org/eye-health/tips-prevention/computer-u…
3. 国家卫生健康委等四部门 (2024). 关于印发《职业病分类和目录》的通知（国卫职健发〔2024〕39 号，「三、职业性眼病」第 2 项电光性眼炎，「六、物理因素所致职业病」第 6 项激光所致眼（角膜、晶状体、视网膜）损伤）. gov.cn/gongbao/2025/issue_11886/202502/conten…