Checking your child's eyes at home: what works, and what apps can and cannot do

Most parents have already done some kind of home check: a glance at the eyes in a photo, a hand held over one eye, a phone app that shows letters. Those checks are worth doing, and worth doing well. They also have limits, and a reassuring result on a screen must never stand in for an examination.

This article separates the two. It says what you can look for at home, what published studies found when apps and devices were compared with a proper examination, and what to do next. No app or brand is named, on purpose.

Can I test my child's eyes at home?

You can watch for signs, but you cannot test vision the way an examination does. At home a parent can notice how the eyes line up, how a child behaves with each eye, and what the eyes look like in a flash photo. A normal result at home does not clear a child. A worrying sign is a reason to book, not to wait.

The reason is that the commonest problems hide. A child with a lazy eye (amblyopia, where one eye's sight has not developed properly) often sees well enough with the other eye and does not complain. The NHS lists signs a parent may notice: shutting one eye or squinting, eyes pointing in different directions, not following an object or person with the eyes, and tilting the head to look at something. The NHS also says treatment should ideally start before the age of 7, while vision is still developing.

What can I look for at home that is actually useful?

Look at four things: whether the eyes point the same way, whether a pupil looks white in a flash photo, whether your child closes one eye or tilts the head to see, and whether your child sits very close to things. Each is free, takes a minute, and can be repeated whenever you are looking at your child anyway.

Start with alignment. A squint (an eye that turns in, out, up or down) needs advice if it is there all the time, or if your child is older than 3 months and it comes and goes, says the NHS. Some babies with a wide, flat nose bridge only look as though an eye turns in, described in our article on pseudostrabismus. If you cannot tell which it is, that is a reason to be checked.

Next, scan old flash photos. The NHS says to ask for an urgent appointment if you notice a white glow or white reflection in the centre of the pupil, which may show in low light or in flash photos. The white glow in photos is the sign here that should move a booking to this week.

Then watch behaviour. The NHS lists frequent eye rubbing, headaches or eye strain, and sitting unusually close to screens among the signs to act on. Teachers often see them first, as in what your child's teacher notices. If an eye drifts when your child is tired, how to spot the drift explains what that means.

Do eye test apps for children work?

Not well enough to rely on, in the recent study that compared a free screening app with a full examination. The app missed about three in ten children who had a risk to their sight development, and flagged many whose eyes were fine. It did worse than the instrument-based screeners used in clinics.

The study was published in the Journal of AAPOS in December 2025. Researchers tested a free photoscreening app (one that photographs the eyes with the phone camera and estimates focusing errors) on 120 children aged 12 months to 12 years, using one phone model. Every child then had an examination with dilating drops, the standard the app was judged against. Sensitivity was 69.7 percent: the share of children with a problem that the app picked up. Specificity was 58.7 percent: the share of children without a problem that it correctly cleared.

Two more numbers matter. When the app said a child had a problem, it was right 52.4 percent of the time. When it said a child was fine, it was right 75.7 percent of the time, so about one in four of the children it passed still had a problem. The children were patients of an eye clinic, so more of them had eye disease than in a general group, which shifts these percentages. It is one app and 120 children, and should not be stretched further. But it points one way: a pass on an app is not a pass at an examination.

Are the photoscreeners clinics use any better?

On the published evidence, yes. A 2019 meta-analysis (a study that pools many studies) of two instrument-based photoscreeners gathered 21 publications and 5,022 children. Sensitivity was 87.7 and 89.4 percent, specificity 78.0 and 89.9 percent, and results were better in children under 7. They are still a screening step: a child who fails is sent for a full examination.

These are dedicated, calibrated instruments, and they still miss some children and refer some who are fine. The American Association for Pediatric Ophthalmology and Strabismus lists photoscreening as an option from 12 months, next to checking the red reflex (the red glow an eye returns to a light) and testing pictures or letters once a child is old enough. A phone app is a different tool in a different setting, and the 2025 study measured that gap.

Can I check my child's sight with a chart or an app at home?

You can, but the result is not reliable enough to reassure you, especially in younger children. An Italian study had families test vision at home with a printable picture chart or a letter chart, then compared the results with a clinic test. Home and clinic scores differed, and agreement was slight for the picture chart in children around 5.

The details: 41 children with a mean age of 5.2 years used the picture chart, and agreement with the clinic reading was 0.12 on a scale where 1 is perfect, which the authors call slight. Older children, mean age 11.6 years, used a letter-chart app or a printed letter chart, with agreement of 0.50 (moderate) for the app and 0.69 (substantial) for the printed chart. All were patients of a children's eye clinic.

The study does not say why, but distance, lighting, guessing and peeking with the covered eye are the usual suspects at home. Whatever the cause, a home chart is a poor way to decide that a young child is fine.

When should my child have a proper eye check, and where do we start in Malaysia?

Book an examination when you notice any sign above, when squint or lazy eye runs in the family, or when your child has never had one. The NHS says an eyesight test is particularly important if childhood eye problems such as squint or lazy eye are in the family, and that children can have a test at any age.

In Malaysia the Ministry of Health's clinic visit schedule lists vision alongside weight, height, hearing and development, so the klinik kesihatan is a natural place to raise a concern. The American Academy of Ophthalmology describes routine vision screening as an important part of a child's medical care, one that finds problems at a stage when many can be treated. If you carry the Buku Rekod Kesihatan, bring it to every visit and ask what was checked in the eyes. To see what an examination involves, including the drops, read the first eye test before school and how we test children's eyes.

AAPOS says to repeat vision screening every one to two years after age 5. The December holidays, when you have time to sit with your child, are a natural moment to look, and to book if you noticed something.

So how should we use home checks in the holidays?

Use them to notice, then act on what you notice. Five minutes of looking is enough: alignment, flash photos, a child closing one eye, sitting close. Write down what you saw, and take the notes and any photos to the examination. Do not use an app to clear your child, and do not let a good score on any screen talk you out of a booking.

If you try an app anyway, treat a poor result as a reason to book. A good result tells you little, because the published numbers show that some children with a real problem pass. Looking is the useful part, and it is already yours to do.

If your child is already being treated for a lazy eye, home games and apps are a different question, covered in lazy eye apps and games.

Common questions

References

1. J AAPOS · Effectiveness of a mobile application in screening for amblyopia risk factors and visually significant refractive error (2025) · pubmed.ncbi.nlm.nih.gov
2. Ophthalmic & Physiological Optics · Diagnostic test accuracy of two photoscreeners in detecting amblyogenic risk factors in children: systematic review and meta-analysis (2019) · pubmed.ncbi.nlm.nih.gov
3. European Journal of Pediatrics · A smartphone app to support paediatric ophthalmology: validation of home visual acuity tests (2023) · pubmed.ncbi.nlm.nih.gov
4. AAPOS · Vision Screening Recommendations · aapos.org
5. NHS · Eye tests for children · www.nhs.uk
6. NHS · Lazy eye (amblyopia) · www.nhs.uk
7. NHS · Squint · www.nhs.uk
8. NHS · Retinoblastoma symptoms · www.nhs.uk
9. American Academy of Ophthalmology · Children's vision screening · www.aao.org
10. Kementerian Kesihatan Malaysia · Jadual lawatan ke Klinik · hq.moh.gov.my

By Dr Chan Li Yen. General information only. It does not replace a consultation. If you are worried about your child's eyes or vision, please see an eye doctor.