Child vision screening: when it is done, the tests, and what a refer result means
The USPSTF recommends vision screening at least once in all children aged 3 to 5 years to detect amblyopia or its risk factors (grade B). (USPSTF, 2017) Amblyopia, also called lazy eye, is the most common cause of vision problems in children. (MedlinePlus, amblyopia) Children may not realise they have a vision problem, so without routine tests a problem may not be spotted. (NHS, eye tests for children)
What amblyopia is
Amblyopia is an alteration in the visual pathway in a child's developing brain that can lead to permanent vision loss in the affected eye. It usually occurs in 1 eye but can occur in both. (USPSTF, 2017) The brain comes to rely more and more on the stronger eye, while vision in the weaker eye gets worse. (NEI, 2024) Among children younger than 6, 1% to 6% have amblyopia or its risk factors. (USPSTF, 2017)
Risk factors
- Eye conditions that can lead to it: strabismus (eyes that do not line up), media opacity such as cataracts, high uncorrected refractive errors (nearsightedness, farsightedness and astigmatism), and anisometropia (a different refractive error in each eye). (USPSTF, 2017) Strabismus is the most common cause of amblyopia. (MedlinePlus, amblyopia)
- Other factors the USPSTF lists: family history in a first-degree relative, prematurity, low birth weight, maternal substance abuse, maternal smoking during pregnancy, and low levels of parental education. (USPSTF, 2017)
- The National Eye Institute adds: children who have developmental disabilities, or a family history of amblyopia, childhood cataracts or other eye conditions. (NEI, 2024)
Amblyopia does not always cause symptoms and is often first diagnosed during an eye test. (NHS, lazy eye) Signs parents may notice include squinting, shutting 1 eye and tilting the head, (NEI, 2024) and eyes that turn in or out, eyes that do not appear to work together, trouble judging depth, and poor vision in one eye. (MedlinePlus, amblyopia) The USPSTF says untreated amblyopia is not likely to resolve on its own. (USPSTF, 2017)
When children are screened
The AAP says vision screening should begin in the newborn nursery and continue throughout childhood. (AAP, 2016) The US and NHS schedules list these checks:
| Age | What is done |
|---|---|
| Newborn to 30 months | AAP: vision risk assessment at each well-child visit, with action if it is positive. NHS: eye checks within 72 hours of birth and at 6 to 8 weeks. (AAP Bright Futures, 2025) (NHS, eye tests for children) |
| 12 and 24 months | AAP: instrument-based screening (an autorefractor or photoscreener) may be used to assess risk. (AAP Bright Futures, 2025) |
| Around 1 year, or 2 to 2½ years | NHS: parents may be asked about any concerns with their child's eyesight at the health and development reviews, and eye tests can be arranged if needed. (NHS, eye tests for children) |
| 3 years | AAP: visual acuity screen in children who can cooperate; instrument-based screening may also be used. USPSTF: screening at least once between 3 and 5 (grade B). (AAP Bright Futures, 2025) (USPSTF, 2017) |
| 4 and 5 years | AAP: visual acuity screen. NHS: vision screening at 4 to 5 years, usually at school. (AAP Bright Futures, 2025) (NHS, eye tests for children) |
| 6, 8, 10, 12 and 15 years | AAP: vision screen; a risk assessment at the other yearly visits. (AAP Bright Futures, 2025) |
The USPSTF did not find enough evidence to set the best interval between screenings for children aged 3 to 5. (USPSTF, 2017) For adults, see eye exams by age.
How screening is done
The USPSTF lists these screening tests used in primary care: (USPSTF, 2017)
- Red reflex test: a light is shone into the eyes and a red reflection should be seen; a white reflection could be a sign of an eye problem. (NHS, eye tests for children)
- Ocular alignment tests: the corneal light reflex test looks for a matching light reflex in both pupils from a light held 2 feet away, and the cover-uncover test looks for alignment changes when one eye is covered or uncovered. (USPSTF, 2017)
- Visual acuity charts: Snellen, Lea Symbols and HOTV charts, with symbols or letters that get smaller. The Lea Symbols chart uses a circle, apple, square and house. (USPSTF, 2017) Each eye is tested one at a time, and numbers, lines or pictures are used for children who cannot read. (MedlinePlus, visual acuity test) In the NHS school test, the child does a letter matching game with one eye covered and does not need to know their letters. (NHS screening leaflet, 2023)
- Photoscreeners and autorefractors: a photoscreener takes camera images of both eyes that a trained observer reviews, and can assess eye alignment, media opacity and visual acuity; an autorefractor estimates refractive error in one eye at a time and does not assess alignment. (USPSTF, 2017) The AAP schedule allows them at 12 and 24 months and at the 3 to 5 year visits. (AAP Bright Futures, 2025)
- Stereoacuity tests: the child wears polarized glasses and is asked to identify a 3-dimensional image on stereo cards. (USPSTF, 2017)
Visual acuity is written as a fraction. 20/20 (6/6) is considered normal; 20/40 (6/12) means the line read at 20 feet can be read by a person with normal vision from 40 feet away. (MedlinePlus, visual acuity test) More: eye exam: what to expect, and 20/40 explained.
What a refer result means
- It is a reason for more tests, not a diagnosis. In England, if screening suggests reduced vision, parents get a letter and the child is referred for further tests at a hospital eye service, a community eye service or a local optometrist. (NHS screening leaflet, 2023)
- The full eye exam is where amblyopia is found. In most cases amblyopia can be detected with a complete eye exam. (MedlinePlus, amblyopia)
- What an abnormal acuity result may point to: MedlinePlus says abnormal results may be a sign of a need for glasses or contacts, or of an eye condition that needs further evaluation by a provider. (MedlinePlus, visual acuity test)
- False positives happen. The USPSTF found false-positive rates usually above 75% in studies of populations where fewer than 10% of children had vision problems, and usually below 35% where more did. False positives may lead to overdiagnosis or unnecessary treatment. (USPSTF, 2017)
- A pass is not a guarantee. Screening should find most problems but may not find every child with reduced vision, and vision changes over time. (NHS screening leaflet, 2023)
MedlinePlus, when to contact a medical professional: "Contact your health care provider or eye doctor if you suspect a vision problem in a young child." (MedlinePlus, amblyopia) The NHS also says to go to an opticians if you are worried about your child's vision. (NHS, lazy eye)
Where they differ:
- Children under 3: the USPSTF found too little evidence to weigh benefits and harms of screening (I statement). (USPSTF, 2017) The AAP lists a vision risk assessment at every visit from birth and allows instrument-based screening at 12 and 24 months. (AAP Bright Futures, 2025)
- How often: the USPSTF recommends screening at least once between 3 and 5 years, (USPSTF, 2017) while the AAP lists a vision screen every year from 3 to 6 and then at 8, 10, 12 and 15. (AAP Bright Futures, 2025) The American Academy of Family Physicians matches the USPSTF. (USPSTF, 2017)
- Screening or a full exam: the USPSTF reports that the American Optometric Association recommends comprehensive eye exams at 6 months, 3 years and before first grade, then every 2 years. (USPSTF, 2017) MedlinePlus says all children should have a complete eye exam at least once between 3 and 5. (MedlinePlus, amblyopia)
- NHS: one vision screening at 4 to 5 years, usually at school, which parents can choose to decline. (NHS screening leaflet, 2023) Where it is not done at school, the NHS says to take the child to a local opticians, and NHS sight tests are free for children under 16. (NHS, eye tests for children)
The USPSTF lists this topic as being updated. (USPSTF, 2017) More: USPSTF grades explained.
Your doctor decides what your result means for you.
This page does not give treatment advice, including on glasses or eye patches. If your child has a refer result, see after an abnormal screening result for questions to ask.
Questions people ask
At what age should a child have a vision screening?
The USPSTF recommends vision screening at least once in all children aged 3 to 5 years (grade B), and found too little evidence to weigh benefits and harms under 3 (I statement). The AAP schedule lists a vision screen at 3 (in children who can cooperate), 4, 5, 6, 8, 10, 12 and 15 years. The NHS offers vision screening at 4 to 5 years. (USPSTF, 2017) (AAP Bright Futures, 2025) (NHS screening leaflet, 2023)
What does a "refer" result on a child vision screening mean?
It means the screening suggests a problem and your child should have further tests. In England, a child whose screening suggests reduced vision is referred to a hospital eye service, a community eye service or an optometrist. A screening result is not a diagnosis: amblyopia is usually found with a complete eye exam. (NHS screening leaflet, 2023) (MedlinePlus, amblyopia)
Is a photoscreener the same as an eye exam?
No. Photoscreeners and autorefractors are screening tools used in primary care to find children who may have a vision problem. A complete eye exam is how amblyopia is detected in most cases. (USPSTF, 2017) (MedlinePlus, amblyopia)
How common is amblyopia?
The USPSTF says 1% to 6% of children younger than 6 have amblyopia or its risk factors. The National Eye Institute says up to 3 out of 100 children have amblyopia. (USPSTF, 2017) (NEI, 2024)
Can my child pass the screening and still have a problem?
Yes. The NHS screening leaflet says vision screening should find most problems but is not perfect and may not find every child with reduced vision, and a child's vision changes over time. (NHS screening leaflet, 2023)