A child who has never seen clearly has no idea anything is wrong. If the whiteboard has always been fuzzy, that’s simply what a whiteboard looks like. If one eye has never pulled its weight, the other one quietly covers for it and the day goes on as normal. Nobody complains, so nothing gets flagged.
That’s what makes children’s vision so easy to miss, and why so many parents only book an appointment after something forces their hand. A teacher mentions the squinting. A child starts inventing reasons not to read. A photo comes back with one eye pointing slightly the wrong way. By then the problem has usually been sitting there for a year or two.
Most childhood sight problems are very fixable when they are picked up early. The difficulty is that “early” means earlier than most people assume.
The short answer: around three, and sooner if anything looks off
If you want one date for the diary, aim for somewhere around your child’s third birthday.
Three works for practical reasons. By that age most children will sit still for twenty minutes and join in with a picture-matching game, which makes the appointment easier and a lot more fun for them. It also leaves a decent runway before school starts, so if there is something to treat, treatment can begin while it still works quickly.
Three is a default, though, not a rule. Optometrists can test a baby, and regularly do. A one-year-old cannot read a chart, but they do not need to.
The newborn checks are not a sight test
You may be thinking your child’s eyes have already been looked at. They have, in a sense. The newborn examination and the six to eight week review both include a check of the eyes. Those checks are hunting for serious abnormalities such as congenital cataract. They aren’t measuring how well your child focuses, whether the two eyes point in the same direction under load, or whether a prescription is quietly building. Passing them tells you very little about whether your four-year-old will need glasses.
Children who should not wait until three
Bring the appointment forward if a parent or sibling has a squint or a lazy eye, or if there are strong prescriptions in the family. The same applies to children born prematurely, and to children with Down’s syndrome, cerebral palsy or a developmental delay, all of which raise the chance of a sight problem that needs managing early.
And if you have a nagging feeling that one eye drifts, or that your child watches the television with their head tilted, don’t wait for a birthday. Parents are usually right about this sort of thing. A sight test takes twenty minutes and costs nothing on the NHS.
Why the first few years count for more than the ones after
Seeing isn’t something the eyes do by themselves. The eyes collect the picture; the brain has to learn how to read it, and it does most of that learning in the first few years of life.
For that learning to go well, the brain needs a sharp, matching image from both eyes. When one eye sends a blurred picture, perhaps because it is far more long-sighted than the other, or because it turns in slightly, the brain does something logical and unhelpful. It starts ignoring that eye. The stronger eye takes over, vision looks fine from the outside, and the weaker eye stops developing. That’s amblyopia, better known as a lazy eye.
This is the bit that decides how the story ends. The brain will relearn the habit for a while, then gradually loses interest. Catch it at four and the fix is often boringly simple: glasses, sometimes a patch worn for an hour or two a day, and the eye catches up. Find the same thing at ten and you are usually looking at permanently reduced vision in that eye, whatever anyone does about it.
An adult with an amblyopic eye copes perfectly well day to day. What they don’t have is a spare. If anything happens to the good eye thirty years later, there is nothing to fall back on. A handful of careers are closed off too, which tends to come as an unwelcome surprise at eighteen.
Children rarely say “I can’t see”, so watch the behaviour instead
Waiting for a child to report a problem doesn’t work, because they have nothing to compare their vision against. What you get instead is behaviour, and it usually gets filed under the wrong heading. Children with uncorrected sight problems get described as dreamy or careless. Some get assessed for everything except their eyes.
Worth acting on:
- Sitting very close to the television, or holding books and tablets right up against their face
- Screwing their eyes up, or covering or closing one eye to look at something
- A head tilt or turn that appears whenever they are concentrating
- One eye that drifts in or out, especially when they’re tired or unwell
- Rubbing their eyes a lot, or watery eyes during reading
- Headaches after school or in the evening once homework starts
- Losing their place, skipping lines, or reading well below what you would expect from how bright they are
- Trouble copying from the board, or complaining they cannot see it
- Clumsiness, and finding it hard to catch a ball, since judging distance takes two eyes working as a pair
- Avoiding anything that needs close attention, such as colouring, jigsaws or reading
Newborn eyes can wander a little in the first weeks while the muscles get coordinated. Past about three months, an eye that keeps turning isn’t something to wait out, and an eye that turns constantly needs checking at any age.
One more sign is less common and more urgent. If a flash photo shows a white or cloudy reflection in one pupil rather than the usual red, get it seen the same day rather than booking for next week. The same goes for a pupil that looks hazy, or an eye that suddenly turns having never done so before. The causes are rare, and they include cataract and, occasionally, a tumour. All of them respond far better to early treatment.
A school vision screening is not the same as an eye test
Plenty of parents assume the reception year screening has this covered. It’s a useful safety net. It’s also a net with wide holes.
Screening usually measures one thing: how clearly each eye reads letters or shapes at distance. It’s quick, it isn’t offered in every part of the country, and a child who is shy, unwell or simply having an off day that morning can slip straight through it.
The bigger gap is long-sightedness. Young eyes have an enormous amount of focusing power, and a long-sighted child can use it to force the distance chart into focus and pass without difficulty. The strain never shows at six metres. It shows at reading distance, twenty minutes into homework, as a headache, and as a slow, growing dislike of books. Screening won’t catch that. Nor will it check colour vision, how well the two eyes work together, or the health of the eye itself.
A full sight test does all of that. It’s a different job.
How we test a three-year-old who cannot read a letter chart
The question we get more than any other is some version of: how can you test her when she can’t read yet? Reading letters is only one way to measure sight, and it is not even the most reliable one.
Most of the useful information comes from retinoscopy. The optometrist shines a light into the eye and watches how the reflection behaves as different lenses are held in front of it. Your child doesn’t have to say a word. They only have to look roughly in the right direction, usually at a cartoon or something interesting on the wall. This is how we work out a prescription for a two-year-old, or for a baby sitting on a parent’s lap.
Everything around that is closer to a game. Matching cards, where the child points at the shape that looks the same instead of naming it. A test where they hunt for a butterfly that seems to float off the page, which tells us whether both eyes are working together. A small light and a paddle to cover each eye in turn, which reveals a turn far too subtle to spot across a kitchen table. Then a look inside the eye with a bright light to check everything is healthy.
Some children need drops. Young focusing muscles are strong enough to mask long-sightedness even during a test, so we relax them with drops and get an honest reading. They sting for a few seconds, then blur near vision and make the eyes sensitive to bright light for a few hours. It’s a fair trade, because the alternative is walking out with a prescription that is simply wrong.
The whole appointment takes about half an hour. Nothing hurts, there are no wrong answers, and a favourite toy is always welcome.
Glasses, follow-up tests, and what the NHS pays for
Sight tests are free on the NHS for anyone under 16, and up to 19 for those still in full-time education. There is also an NHS optical voucher towards glasses, which covers a complete pair at most practices. Cost shouldn’t be the reason this gets put off.
After the first test, once a year is the usual rhythm. Children’s eyes change as they grow, and a prescription that was right in Year 2 often isn’t by Year 4. Some children come back every six months, normally when we are treating a lazy eye, watching a squint, or following a prescription that is moving quickly.
Not every prescription means glasses. A degree of long-sightedness is entirely normal in a young child, and most grow out of it without ever wearing a lens. A good optometrist will happily tell you the answer is “nothing, come back in a year” instead of walking you over to the frames.
When glasses are needed, let your child choose them. That sounds like a small thing and it isn’t. A pair they hate lives at the bottom of a bag or gets lost on purpose, and a lens that is not in front of an eye does no good at all. Children adapt to glasses far faster than adults, usually inside a week, as long as they don’t feel self-conscious in them. Ask about repairs and replacements while you are there. Children break glasses. There is normally a way to sort it out.
Short sight is starting earlier, and what you can do between tests
More children are becoming short-sighted, and they are becoming short-sighted younger than they used to. It tends to appear during the primary school years, often alongside a growth spurt, and once it starts it usually keeps creeping up until the late teens.
Distance vision goes first. The board gets harder to read while books stay easy. They screw their eyes up to read the number on the bus, or shuffle closer to the television. Reading is unaffected, which is exactly why parents often don’t suspect the eyes.
There is more at stake here than lens thickness. A very short-sighted eye is a physically longer eye, and a longer eye carries a higher risk of retinal problems in adult life. Slowing the progression while a child is young is therefore worth real effort, which is why a growing number of UK practices now offer myopia management: spectacle lenses designed to slow the eye’s growth, daily disposable contact lenses that do a similar job, and in some cases low-dose atropine drops. These work best when they are started early, because early is when short sight moves fastest.
Habits will not override genetics, but they do help:
- Get them outside. Around two hours of daylight a day seems to make a real difference to whether short sight starts at all, and it’s the daylight doing the work, not the running around.
- Watch the working distance. A book or tablet pressed against the nose is far harder work than the same thing held at a comfortable arm’s length.
- Break up close work. Looking out of the window for a moment every twenty minutes or so is enough.
- Keep an eye on phones. They get held closer than anything else, and the time on them creeps up quietly.
- Light the homework properly. In a dim room, children edge closer to the page without realising.
If both parents are short-sighted, assume your child stands a fair chance of it as well, and don’t let the gap between appointments stretch.
Book it before you have a reason to
The trigger for a child’s first eye test should never be a symptom. Symptoms turn up late, and in children they usually turn up disguised as something else: bad behaviour, or a child who has quietly gone off reading. The one who most needs testing is often the one showing you nothing at all.
So: around three, sooner if anything on the risk list sounds like your family, then roughly once a year after that. It’s free, it takes half an hour, and it either finds something at the age when finding it still changes the outcome, or it tells you there is nothing to worry about. The second answer is worth having too.
The case for testing early is only getting stronger. Children now spend much of the day looking at things held a few inches from their face, and short sight is arriving earlier as a result. The methods for slowing it down keep improving, but nearly all of them come with the same condition attached: they work best when they start early. That only happens if somebody looks.
If your child has never had a sight test, or the last one is a hazy memory, book one. It’s NHS funded, and there’s no age too young to walk through the door.
FAQs
At what age should my child have their first eye test?
Around three for most children, before they start school. Bring it forward if there is a family history of squint, lazy eye or strong prescriptions, if your child was premature, or if you have noticed anything unusual. There’s no lower age limit.
Are children’s eye tests free in the UK?
Yes. The NHS covers a sight test for anyone under 16, and under 19 if they are in full-time education. You also get an NHS optical voucher towards glasses, which pays for a full pair at most practices.
Can my child be tested if they cannot read or talk yet?
Yes. Retinoscopy measures the prescription with light and lenses and needs no answers at all, so it works on babies and toddlers. Picture charts and matching cards cover the rest. Some young children also need drops to relax the focusing muscles, which sting briefly and blur near vision for a few hours.
My child passed the school vision screening. Do they still need an eye test?
Yes. Screening normally checks distance vision only, is not offered everywhere, and misses long-sightedness, focusing and eye teaming problems, colour vision and eye health. It’s a filter, not a full examination.
How often should children have their eyes tested?
Once a year for most children. Every six months if we are monitoring a lazy eye, a squint, or a prescription that is changing fast. Come in sooner if you notice a change in how your child sees or behaves.
