Children rarely complain that they cannot see well — they simply do not know what normal vision looks like. This makes early detection of childhood eye conditions entirely dependent on parents, school nurses and routine vision screening. As a consultant with fellowship training in paediatric ophthalmology, this is an area I see profoundly undertreated.
Squint (strabismus) — one eye turning in or out
A squint, where one eye turns inward (esotropia), outward (exotropia), upward or downward relative to the other, is one of the most common paediatric eye conditions, affecting around 2–3% of children. It is never normal after the age of 3–4 months.
Untreated squint leads to amblyopia (see below). Treatment depends on the type and may involve glasses, patching of the better eye, or surgery to realign the eye muscles.
- Watch for: one eye that consistently turns in a different direction, or eyes that look misaligned in photographs.
- Note: a child squinting (narrowing the eyes) in bright light is different — this is usually just light sensitivity, not a squint.
- Pseudostrabismus: in babies and young toddlers, wide nasal bridges can make the eyes look crossed when they are actually straight. A paediatric ophthalmologist can confirm alignment.
Amblyopia — the 'lazy eye'
Amblyopia is a reduction in visual acuity in one eye that cannot be corrected by glasses alone. It develops when the brain receives a blurred or misaligned image from one eye during the critical visual development period (birth to approximately age 8) and begins to suppress that eye's input.
The most important thing to understand about amblyopia is that the window for effective treatment closes in late childhood. Treatment with patching or penalisation drops is highly effective before age 7–8, much less so after. Early detection is critical.
- Causes: squint, significant refractive error (short-sight, long-sight, astigmatism) — especially if different between the two eyes, or anything that obscures the visual axis (congenital cataract, significant ptosis).
- Symptoms in children: often none. The child uses their better eye and does not complain.
- Red flag: covering one eye causes immediate distress or protest — this strongly suggests the uncovered eye has poor vision.
Refractive errors — glasses at a young age
Long-sightedness (hyperopia), short-sightedness (myopia) and astigmatism all affect children. Significant or asymmetric refractive errors are the most common cause of amblyopia. Children should have their vision checked by a trained optometrist from age 3, or earlier if there is a family history of squint, high glasses prescription, or lazy eye.
Myopia (short-sightedness) has been increasing rapidly in children over recent decades, particularly linked to increased near work and reduced outdoor time.
Blocked tear ducts (nasolacrimal duct obstruction)
Around 5% of babies are born with a blocked nasolacrimal duct — the channel that drains tears from the eye to the nose. This causes persistent watering of one or both eyes with discharge, particularly on waking. It is not painful and does not harm vision.
In 90% of cases it resolves spontaneously by age 12 months with massage of the lacrimal sac. If it persists beyond 12–18 months, a brief syringing procedure under general anaesthetic (probing) is curative in most cases.
When to refer your child to a paediatric ophthalmologist
- Any visible squint or eye turn at any age after 3–4 months.
- A failed school or pre-school vision screening.
- Family history of squint, amblyopia, or high glasses prescription.
- One eye appearing larger or with a white reflex (leukocoria) — always urgent.
- Persistent watering and discharge not resolved by age 12–15 months.
- Drooping eyelid (ptosis) that covers the pupil.
- Any sudden change in a child's vision or eyes.
Frequently Asked Questions
At what age should children have their eyes tested?
In the UK, all children should have a vision screening check before they start school (around age 4–5). However, if there is any concern — family history of squint, amblyopia, or high glasses prescription — children should be seen by an optometrist from age 3, or even earlier if a problem is suspected. A child is never too young to have their eyes examined.
My child's eye turns in only when they are tired. Is that normal?
An intermittent squint that appears when a child is tired, unwell or concentrating is still a squint and warrants assessment by a paediatric ophthalmologist or orthoptist. Intermittent squints can progress and can still cause amblyopia in the suppressed eye.
Is patching treatment for lazy eye unpleasant for children?
Patching is indeed challenging for young children — covering the better eye makes their vision worse in the short term, which they naturally resist. Strategies include: starting with short periods (1–2 hours daily) and building up, using rewards/stickers, involving the child in choosing patches, and in some cases using atropine drops instead of a patch. Compliance improves significantly when parents understand the reason for treatment and the time-sensitive nature of the window for improvement.
Mr Mohamed Mohyudin
MBChB BSc MSc FRCOphth CCT — Consultant Ophthalmic Surgeon, Spire Elland Hospital, Yorkshire. GMC 7039600.
View full credentials →