Don’t buy blue-light-blocking glasses to “protect your vision,” and don’t believe claims that staring at screens for months will ruin your eyes — but eye pain, swelling, and redness require urgent medical care.

These glasses cost nothing, and you’ll also avoid paying the extra few hundred to a few thousand dollars for special blue-light-blocking lenses.

A 2023 Cochrane systematic review analyzed 17 randomized controlled trials involving 5 to 156 participants each, with follow-up periods ranging from less than a day to five weeks. Due to limited data, significant differences in participant numbers, and inconsistent follow-up times, the authors did not combine results into a single overall figure. All results below compare participants wearing blue-light-blocking lenses to those wearing regular lenses. After less than a week, self-reported eye fatigue showed “possibly no difference” between groups, though evidence certainty was low. One trial with 120 participants found a 9.76-unit difference between groups; this difference’s 95% confidence interval ranged from −33.95 to 53.47, indicating no meaningful distinction. Critical flicker fusion frequency, an objective measure of eye fatigue, also showed “possibly almost no difference” between groups, with low evidence certainty. Best-corrected visual acuity remained “likely unaffected” after wearing these lenses; the difference between groups was 0.00 logMAR (95% CI −0.02 to 0.02), based on a single study with 156 participants and moderate evidence certainty. Whether these lenses affect daytime alertness remains unclear (two trials, 42 participants; very low evidence certainty). The review found no evidence supporting their ability to protect the retinal macula.

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. https://doi.org/10.1002/14651858.CD013244.pub2

Screen use commonly causes eye strain and dryness, manifesting as soreness, dryness, and temporary blurriness. These symptoms can be relieved by resting your eyes and blinking more often; they do not indicate permanent eye damage. This viewpoint is widely accepted in ophthalmology but is not a conclusion drawn from the Cochrane review cited here, so it is classified as evidence grade C. Only intense light sources such as welding arcs, ultraviolet radiation, and lasers can cause irreversible eye damage in a short time. Eye injury from welding arcs, known as “arc eye,” is a legally recognized occupational disease; protection requires specialized goggles and face shields, not blue-light-blocking lenses (see Section 19, Item 11 on protection against dust, noise, and chemical hazards). Staring at screens for long periods without adequate rest poses no inherent risk, except in rare cases: sudden eye pain, swelling, redness, halos around lights, headaches, and nausea may signal acute angle-closure glaucoma, a condition that can damage the optic nerve within days; such symptoms demand immediate emergency eye care (see Section 13, Item 6 on eye emergencies). People over 50, those with hyperopia, and individuals with shallow anterior eye chambers are at higher risk due to factors such as dilated pupils in dim light and prolonged forward head posture. Chronic dry eye caused by screen use may eventually require medical treatment, rather than resolving on its own after a night’s sleep. Persistent eye discomfort or declining vision warrants a professional eye examination rather than simply purchasing new lenses. For information on preventing myopia in children and teens, see Section 30, Items 4, 12, and 9 (daily outdoor time, dilated eye exams, and avoiding products claiming to “cure” myopia).