The link between screen time and short-sightedness is real — but it's more nuanced than "screens are bad." Here's what the research actually says, and what you can do about it.
Reviewed by Dr Mark Joung & Dr Vivian Li · Last updated May 2026
A 2025 meta-analysis in JAMA Network Open (Ha et al., 45 studies, 335,524 children) found that each additional hour of daily screen time raised the odds of myopia by about 21%. But the International Myopia Institute's 2025 Digest — authored in part by researchers at the Brien Holden Vision Institute in Sydney — was careful to note that the evidence linking screens specifically to myopia remains "inconsistent," and that the rise of myopia in East Asia began well before smartphones existed.
So what's really going on? When children are on screens, three things tend to happen at once: they hold the device close to their face (often closer than 20 cm), they stay focused at that distance for long stretches without breaks, and they're indoors instead of outside. Each of those three factors independently contributes to myopia risk. The screen is the vehicle — the close distance, sustained focus, and missing outdoor time are the engine.
That last number is worth pausing on. An Irish study of 723 schoolchildren found that 6-to-7-year-olds with more than two hours of daily screen time had approximately ten times higher odds of myopia or premyopia compared to light users. By ages 12–13, the difference was much smaller. The takeaway: screen habits matter most in the early primary school years, when eyes are still developing rapidly.
Not all screen time is equal, either. Watching television from across the room (3+ metres) is very different from holding a tablet 20 cm from your face. Working distance matters more than screen time per se — a child reading a book at 15 cm creates the same accommodative demand as a phone at the same distance.
Outdoor light is the key. Natural daylight ranges from 11,000 to 18,000 lux — roughly 100 times brighter than indoor lighting. Even sitting under a tree in the shade with a hat on exceeds the 1,000-lux threshold researchers believe triggers protective dopamine release in the retina. It doesn't have to be sport. Walking to school, eating breakfast in the backyard, playing in the park after school — it all counts.
A meta-analysis by Xiong, Sankaridurg and colleagues at the Brien Holden Vision Institute (2017) calculated that an additional 76 minutes of daily outdoor time corresponded to a 50% reduction in the risk of developing myopia.
A landmark study of over 123,000 Chinese children (Wang et al., JAMA Ophthalmology 2021) found a myopic shift of −0.3 dioptres in 6-to-8-year-olds during home confinement — with myopia prevalence rising up to three times above the five-year baseline. A 2023 meta-analysis (Laan et al.) pooled data across multiple countries and found an average change of −0.83 dioptres and +0.36 mm of axial elongation during the COVID period compared to before.
Professor Padmaja Sankaridurg at the Brien Holden Vision Institute (UNSW, Sydney) reported that Australian practitioners were seeing progression rates roughly double what they'd normally expect over the same period.
Pseudomyopia can improve with reduced near work and visual breaks. It's one reason a child's vision might seem to "get better" after a screen-free holiday. But without proper testing, there's no way to tell pseudomyopia from true axial myopia — and the risk of misdiagnosis matters. If a child with pseudomyopia is prescribed full-strength minus lenses, the over-correction may itself encourage the eye to elongate.
This is why we use cycloplegic refraction — eye drops that temporarily relax the focusing muscles — as part of our paediatric assessment. It's the gold standard for distinguishing true myopia from accommodative spasm, and it's especially important for children with high screen exposure whose focusing systems may be under strain.
Limit leisure screen time (not schoolwork) to two hours or less per day. This aligns with the Australian Government's 24-Hour Movement Guidelines. For under-5s, the limit is one hour.
Aim for at least two hours of outdoor time each day — in any weather, any activity. Walking to school, eating outside, and playing in the yard all count. It's the daylight that matters, not the exercise.
Use the 20-20 rule: every 20 minutes, look at something at least 6 metres away for 20 seconds. For working distance, use the elbow rule — the screen should never be closer than the distance from fist to elbow.
If your child already uses an iPhone or iPad, turn on the built-in Screen Distance feature (Settings → Screen Time → Screen Distance). It alerts your child when the device is closer than 30 cm from their face — a practical digital enforcement of the elbow rule.
Watching TV from a normal viewing distance (3+ metres) carries much less risk than handheld devices held close to the face. The key factor isn't the screen itself — it's how close your child holds it and how long they look without a break. A tablet at 20 cm is very different from a television across the room.
No. Any time spent outdoors in natural daylight counts — walking, playing, eating outside, even sitting in the shade reading a book. Research shows the protective effect comes from exposure to bright outdoor light (1,000+ lux), not from physical activity specifically.
School-related screen time is different from recreational use. Focus on working distance (use the elbow rule), regular breaks (every 20 minutes), and compensating with outdoor time before or after school. The two-hour guideline applies to leisure screens, not educational use.
Screens may be contributing, but progressive myopia usually has multiple factors — genetics, reduced outdoor time, sustained near work, and the child's age. If your child's prescription is changing more than −0.50 dioptres per year, it's worth discussing myopia control options that can slow progression by 50–60%.
The early primary school years (ages 5–8) appear to be the most critical window. Research shows that 6-to-7-year-olds with heavy screen use are approximately five times more likely to be myopic than light users — an effect that diminishes significantly by ages 12–13, likely because the visual system has matured.
Blue-light filtering glasses may reduce digital eye strain symptoms (tiredness, dry eyes), but there is no evidence they prevent or slow myopia. The factors that matter for myopia are working distance, duration of near work, and outdoor time — not the colour spectrum of the screen.
Plain-English guide to short-sightedness — what causes it, why it matters, and when to act.
Evidence-based myopia control with transparent pricing. Ortho-K, MiyoSmart, MiSight, and atropine.
Overnight lenses that correct vision while your child sleeps — and slow myopia progression by 50–60%.
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Dr Mark Joung
B.Optom (Hons) UNSW · Certificate in Ocular Therapeutics (ACO) · 800+ Ortho-K fits · One of the first Australian optometrists to fit MiyoSmart
Dr Vivian Li
B.Optom (Hons) UNSW · Grad Cert Ocular Therapeutics · ACO Advanced Certificate in Children's Vision
References
Ha A, Lee YJ, Lee M, et al. Digital Screen Time and Myopia: A Systematic Review and Dose-Response Meta-Analysis. JAMA Network Open. 2025;8(2):e2460026.
Rose KA, Morgan IG, Ip J, et al. Outdoor Activity Reduces the Prevalence of Myopia in Children. Ophthalmology. 2008;115:1279–85.
Xiong S, Sankaridurg P, Naduvilath T, et al. Time spent in outdoor activities in relation to myopia prevention and control. Acta Ophthalmologica. 2017;95:551–566.
Harrington S, O'Dwyer V. The association between time spent on screens and reading with myopia in 6- to 7-year-old schoolchildren in Ireland. Ophthalmic Physiol Opt. 2023;43(3):505–516.
Wang J, Li Y, Musch DC, et al. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. JAMA Ophthalmology. 2021;139(3):293–300.
Tahhan N, Bullimore MA, He X, et al. IMI—2025 Digest. Invest Ophthalmol Vis Sci. 2025;66(12):27.
Holden BA, Fricke TR, Wilson DA, et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016;123(5):1036–42.
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