When it happens · 3 min read
Sitting too close to the TV, and squinting
They have started sitting a foot from the television, holding books almost against their face, or screwing their eyes up to look at something across the park. Someone has probably already told you that sitting that close is what causes it.
It is the other way round. Sitting close is how a short-sighted child gets a clear picture, and it is one of the more reliable signs that it is time to get their eyes tested.
Last updated August 17, 2026
What to look for
Sitting very close to a screen, or holding books and tablets unusually close. Screwing the eyes up to see anything at distance. Tilting or turning the head to look at something. Rubbing the eyes a lot, headaches, or tiring quickly with anything that needs looking at.
Later, once they are at school: not being able to read the board, or copying from the child next to them rather than the front of the room.
The reason children rarely complain is that they have no basis for comparison. A child who has always been short-sighted does not know that other people can read a sign from across the road, so the absence of a complaint tells you nothing.
What the outdoor evidence actually says
Children who spend more time outdoors are less likely to become short-sighted. That finding has held up across large studies, and it appears to be independent of how much time is spent reading or on close work — so it is not simply that outdoor children read less.
The mechanism is not settled. The leading idea is that it is about light exposure rather than about distance vision or exercise, but that is still a hypothesis rather than a conclusion.
This is worth acting on because outdoor time is good for a long list of other reasons anyway, but it is a shift in the odds rather than a preventive measure. It will not correct short-sightedness that has already developed, and it is not a substitute for glasses.
What doesn't cause it
Reading in dim light, sitting close to the television, and looking at screens do not cause short-sightedness in the way the folk advice suggests, and the child who is doing all three is usually doing them because they cannot see well.
There is a genuine question about time spent on close work indoors, and it is bound up with the outdoor findings above. That is not the same claim as any of the above, and it is worth keeping the two separate when someone tells you the tablet did this.
What happens next
An eye test. Glasses correct it, and there is no benefit in delaying them or in trying to get by with weaker ones.
Short-sightedness usually appears in the school years and tends to progress into the early twenties before settling, so expect the prescription to change and expect to be back for checks.
There are treatments aimed specifically at slowing progression, rather than just correcting the vision, and they are an active research area. If it is progressing quickly, that is a conversation worth having rather than waiting to be offered.
Common questions
- Will glasses make their eyes worse or make them dependent?
- No. Glasses correct the focus while they are worn and do not accelerate the underlying change. Going without them just means seeing badly.
- They passed a school vision screening. Could they still be short-sighted?
- Yes. Screenings catch a lot but not everything, and they are a snapshot. If you are seeing the signs at home, get a proper eye examination rather than relying on a screen having been passed.
- How much outdoor time are we talking about?
- The studies point at daily time outdoors rather than a specific prescription, and the effect is on the odds of developing it rather than a guarantee either way. Treat it as one good reason among several to be outside, not as treatment.
If it's this, not that
Still not sure
This page is the general answer. Yours is a specific child.
The advisor can be. It has read everything here, and it knows how old your children actually are — which is the whole difference wherever guidance changes with age. Ask it anything.
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Where this comes from
Every claim on this page traces to one of these. See every source we use →
Written from the sources named above, and it is not a substitute for your own doctor. If something feels wrong to you, that instinct is a good enough reason to call — you know yourself and this family better than any page does.