2 hours outdoors a day
What it is
Daylight time protects eyesight (school-age trials cut new myopia), sleep, mood and movement; it delays onset, not existing myopia.
Always on
- The eyesight evidence is strongest from age 6; under 6 it is still great for sleep, movement and mood.
- Already wears glasses? Outdoor time will not slow the progression — keep it for everything else it gives.
- School-day math: recess outside + walking to school + an afternoon at the park adds up to 2 hours.
Sources
- Physical activity, sedentary behaviour and sleep for children under 5 (2019) — World Health Organization
- Outdoor time at school and myopia (cluster RCT, JAMA 314(11)) — He et al., JAMA
- Outdoor recess reduces myopia onset (Ophthalmology 120) — Wu et al., Ophthalmology
- Myopia prevention and outdoor light intensity (cluster RCT, Ophthalmology 125) — Wu et al., Ophthalmology
- Increased outdoor time reversed the visual-acuity trend in Taiwan (Ophthalmology 127) — Wu et al., Ophthalmology
- Outdoor time and myopia prevention meta-analysis (Acta Ophthalmologica 95) — Xiong et al., Acta Ophthalmologica
- Role of light in refractive error; ≥2 h/day outdoors recommendation — International Myopia Institute
Compiled with AI assistance from the public sources listed above. Not yet reviewed by a clinician — check anything important against the source, with Tipat Halav or with your doctor.