Does Outdoor Time Still Matter Once My Child Is Short-Sighted?
- John Nguyen
- 11 minutes ago
- 5 min read
By John Nguyen
Your child is already wearing myopia control lenses or using atropine drops. So does getting outside still count for anything? Recent research suggests it may, and points to when it matters most.
Most parents hear the outdoor advice early. Get your child outside, two hours a day, and you reduce the chance they become short-sighted in the first place. That part is well established.
What is far less clear is what happens next. Once a child is already short-sighted and started on treatment, the conversation usually moves on to lenses and drops, and the outdoor advice quietly drops down the list. Parents notice this. If it was so important last year, why does nobody mention it now?
The honest answer is that researchers have not settled the question. But some recent findings make it worth keeping up, and they point to a particular time of year when it may matter most.
Children’s eyes grow faster in winter
This is one of the more consistent findings in myopia research, and it has been shown for over a decade. Eyes lengthen faster during the darker months and slow down over summer. One study found children’s prescriptions changed almost twice as fast over winter as over summer.1 The same pattern has turned up in children in the United States2 and in Europe.3
Nobody is certain why. More daylight in summer is the obvious explanation, and there is good reason to think light plays a part.4 But summer also brings school holidays, which means less reading and homework, so the two things move together and researchers have not been able to separate them.
The new part: it still happens during treatment
Here is what has changed recently, and it is the reason this is worth your attention.
Three studies published in the last eighteen months looked at children who were already having myopia treatment, and asked whether that seasonal difference still showed up.
It did. In a study of 600 children wearing ortho-k lenses overnight, eyes grew noticeably faster over the winter half of the year than the summer half.5 A second ortho-k study found the same thing.6 The third is the most interesting for parents, because it looked at two different treatments side by side: children in myopia control spectacles combined with atropine drops, and children in ortho-k. The seasonal difference appeared in both groups.7
In plain terms, the treatment is working, but it is not flattening out the seasonal effect. Something about winter is still pushing eye growth along, even in children who are being actively treated.
What this does and does not tell us
It is worth being straight about the limits here. None of these studies measured how much daylight the children actually got, so none of them can prove that light is the reason. They were all done in northern China, and they looked back at existing records rather than being set up in advance. That makes them a useful signal rather than an answer.
And the bigger question, whether more time outdoors slows myopia down once a child is already short-sighted, has genuinely not been settled either way. Some studies suggest it helps, others do not find a clear benefit. Researchers are still working on it, partly because most studies have simply asked how many hours children spent outside, which treats a shady late afternoon and a bright midday hour as the same thing when they are nothing alike.
So this is not a case of new evidence proving that daylight slows progression. It is a case of a signal that keeps showing up, including in children on treatment, that nobody can yet fully explain.
Why we still suggest it
Given all that uncertainty, why keep pushing outdoor time at all?
Because the reasons for doing it have not gone away. Time outdoors is well proven for preventing myopia in the first place, and there is no obvious reason the underlying effect would simply switch off the day your child gets their diagnosis. It costs nothing, it is safe with sensible sun protection, and it brings all the other benefits of an active childhood.
Outdoor time was never going to control your child’s myopia by itself, and no eye care professional would suggest it should. But sitting alongside their lenses or drops, it remains a sensible part of the plan rather than an optional extra.
What to do with this
Keep it going after diagnosis. Starting treatment is not a reason to stop the outdoor habit. Think of the two as working together.
Expect winter to be the harder stretch. Short days, cold weather and dark afternoons make outdoor time the first thing to disappear. If you are going to make an effort at any point in the year, make it then.
Use the daylight you have. Walking to school, the school break, a short trip to the park after school, weekend mornings. Sitting near a bright window may well help, but going outside is likely to be better still.
Ask at the next appointment. Ask your optometrist how your child’s eye growth is tracking, and mention what their outdoor routine actually looks like. It is a useful part of the picture and is often not discussed.
Do not swap it for the treatment. Outdoor time is an addition to whatever your child has been prescribed, never a replacement, and never a reason to skip drops or lens wear.
The short version: your child’s treatment is doing important work, but the seasons still seem to have a say. Getting outside remains worth the effort, and never more so than in the middle of winter when it is the last thing anyone feels like doing.
References
Donovan L, Sankaridurg P, Ho A, et al. Myopia progression in Chinese children is slower in summer than in winter. Optometry and Vision Science. 2012;89(8):1196-1202. https://doi.org/10.1097/OPX.0b013e3182640996
Gwiazda J, Deng L, Manny R, Norton TT. Seasonal variations in the progression of myopia in children enrolled in the Correction of Myopia Evaluation Trial. Investigative Ophthalmology & Visual Science. 2014;55(2):752-758. https://doi.org/10.1167/iovs.13-13029
Hecova L, Rusnak S, Salcman V, Cendelin J. Seasonal variations in ocular axial length increase among children in the Czech Republic. Journal of Ophthalmology. 2023;2023:2592853. https://doi.org/10.1155/2023/2592853
Lingham G, Mackey DA, Lucas R, Yazar S. How does spending time outdoors protect against myopia? A review. British Journal of Ophthalmology. 2020;104(5):593-599. https://doi.org/10.1136/bjophthalmol-2019-314675
Ding W, Zhao C, Li X, et al. Seasonal variation in axial elongation in children with orthokeratology treatment. Ophthalmic and Physiological Optics. 2025;45(3):877-882. https://doi.org/10.1111/opo.13486
Tang T, Li Y, Zhao M, Wang K. Seasonal variation in the effect of controlling myopia progression using orthokeratology. Eye & Contact Lens. 2025;51(9):394-399. https://doi.org/10.1097/ICL.0000000000001205
Li X, Zhao C, Yin M, et al. Comparison of seasonal variation in myopia progression: defocus incorporated multiple segment spectacle lenses in combination with 0.01% atropine vs orthokeratology. Clinical Ophthalmology. 2026;20:582774. https://doi.org/10.2147/OPTH.S582774
About the author
John Nguyen is an Australian optometrist and the founder of Luxi Health, which develops daylight-tracking technology to encourage healthy daylight habits in children. He built Zoom Optics into a group of practices across Sydney, and writes and speaks internationally on myopia. He has a particular interest in the role of outdoor light and the wider visual environment in healthy eye development.
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