A turned eye in a child is not something to watch and wait on. Early treatment makes a real difference, and the results are often better than parents expect.

Strabismus is a condition in which the two eyes do not point in the same direction at the same time. One eye looks straight ahead while the other turns inward, outward, upward, or downward. It affects around 4 percent of children and can also develop in adults following neurological events, injury, or thyroid disease. In children, strabismus is closely linked to amblyopia and requires prompt treatment. In adults, it typically causes double vision and significant quality of life impact. Both groups have good treatment options.

What You Need to Know About Strabismus

Strabismus means the eyes are misaligned: one eye turns in a different direction from the other
It is not caused by weakness or laziness of the child. It is a neuromuscular coordination problem that is not the child’s fault
Left untreated in children, strabismus causes the brain to suppress the turned eye, leading to amblyopia
Some strabismus in children is caused by uncorrected long-sightedness and is corrected entirely by glasses
Surgery is effective and often produces excellent alignment, but glasses and patching may still be needed afterward
Adults who develop a sudden new squint require urgent assessment to exclude a neurological cause

How common ~4% Of children are affected by strabismus

Glasses alone ~30% Of accommodative esotropia cases fully correct with glasses only

Surgery success ~80% Of patients achieve good alignment after one procedure

Types of Strabismus

Esotropia

One eye turns inward toward the nose. The most common type in young children. Infantile esotropia appears in the first six months of life and requires surgery. Accommodative esotropia appears between ages 2 and 4 and is driven by uncorrected long-sightedness: the child’s efforts to focus for near vision cause the eyes to over-converge. Glasses that correct the long-sightedness can eliminate or greatly reduce the turn. A child who suddenly develops a convergent squint at age 2 to 3 should have a refraction done under cycloplegia as a first step before considering surgery.

Exotropia

One eye turns outward away from the nose. Often intermittent at first, noticed most when the child is tired, daydreaming, or looking into the distance. Many children with intermittent exotropia compensate well for years. Parents often notice one eye drifting outward in bright sunlight and the child squinting or closing that eye. Constant exotropia is less common than constant esotropia in children but becomes the more prevalent pattern in adults with longstanding strabismus.

Vertical strabismus

One eye turns upward (hypertropia) or downward (hypotropia) relative to the other. Can occur in isolation or alongside a horizontal deviation. Common causes include fourth nerve palsy, which causes the affected eye to tilt and the patient to adopt a characteristic head tilt to compensate, thyroid eye disease causing restrictive myopathy, and Brown syndrome, in which the superior oblique tendon restricts upward gaze in adduction. Vertical strabismus in adults with double vision requires careful workup to identify the cause before planning treatment.

Why Does Strabismus Develop?

In children

In most children, strabismus does not have a single identifiable cause. There is often a hereditary component: a parent or sibling with a squint raises the risk noticeably. Uncorrected refractive errors, particularly long-sightedness, are a major contributing factor for accommodative esotropia. Premature birth, developmental delay, and certain neurological conditions are associated with higher rates of strabismus. Rarely, a new squint in a child can be caused by a tumour or neurological lesion: a child who develops any new squint should be assessed promptly rather than observed.

In adults

A new squint in an adult with double vision has a different set of causes from childhood strabismus. Cranial nerve palsies (third, fourth, or sixth nerve) from microvascular ischaemia in patients with hypertension or diabetes are common. Thyroid eye disease causes restrictive myopathy that limits eye movement and produces vertical or horizontal double vision. Myasthenia gravis produces a variable strabismus that worsens with fatigue. Mechanical causes include orbital fractures and prior surgery. A new onset squint with diplopia in an adult always warrants neurological investigation.

Strabismus and Amblyopia

These two conditions are inseparable. When the eyes are misaligned, the brain receives two different images simultaneously. To avoid double vision, the brain suppresses the image from the turned eye. This suppression, sustained during the critical period of visual development in childhood, leads to amblyopia: the suppressed eye fails to develop normal visual acuity, and that reduction in vision becomes permanent if not treated in time.

Treating strabismus without also treating the amblyopia it has caused is only half the job. Surgery aligns the eyes. Patching or atropine develops the vision in the amblyopic eye. Both are needed, and the younger the child when treatment starts, the better the outcome for both alignment and vision.

Treatment

Glasses

For accommodative esotropia, glasses correcting the underlying long-sightedness are the first step and sometimes the only treatment needed. The glasses need to be worn full-time, not just for near work, because the accommodative drive that causes the convergence operates at distance too. Parents sometimes resist full-time glasses in a two-year-old, but early compliance is critical. Some children’s accommodative esotropia fully resolves with glasses alone. Others achieve partial correction and need surgery for the residual deviation.

Patching and amblyopia treatment

Patching the dominant eye forces the brain to use the turned eye and develops its visual acuity. This is amblyopia treatment, not strabismus treatment: it improves the vision in the weaker eye but does not straighten it. It is done before surgery in children with significant amblyopia to maximise vision in both eyes, because a child with poor vision in the non-dominant eye makes a much better surgical candidate than one who is entirely dependent on a single eye.

Surgery

Strabismus surgery adjusts the tension on one or more of the muscles that move the eye, either weakening an overacting muscle or strengthening an underacting one. It is performed under general anaesthetic, typically as a day procedure. The eye is red and sore for a week or two afterward, which looks alarming but is normal. Most patients achieve good alignment from a single procedure; some need a second operation to fine-tune the result.

Before and after comparison showing a child's eyes with esotropia on the left with one eye turning inward, and straight aligned eyes on the right after treatment — Left: esotropia before treatment. Right: straight eyes after treatment. Around 80 percent of patients achieve good alignment after a single procedure.

Botulinum toxin injection

Botulinum toxin injected into an overacting extraocular muscle temporarily weakens it, allowing the opposing muscle to bring the eye back toward alignment. The effect lasts two to four months and may produce lasting correction in some cases, particularly recent-onset strabismus from a cranial nerve palsy that may recover spontaneously. It is most useful as a temporary measure or as an alternative to surgery in selected patients.

Prism glasses

Prism lenses bend light before it enters the eye, compensating for the deviation and eliminating double vision in adults with strabismus. They do not treat the underlying deviation but provide symptomatic relief. Temporary stick-on Fresnel prisms are used to assess whether a prism will be helpful before incorporating permanent prism into spectacle lenses. Useful for small stable deviations, less practical for large deviations where the prism thickness becomes optically limiting.

What Surgery Can and Cannot Do

Many parents come in with mismatched expectations, so let’s be direct about what surgery does and doesn’t do. Strabismus surgery repositions the eyes. It does not fix the brain’s processing of vision from the turned eye. A child who has had surgery and is now cosmetically aligned still needs to be monitored for amblyopia and may still need patching afterward. Surgery is one step in the treatment, not the endpoint.

The cosmetic outcome matters genuinely. Strabismus affects how others perceive a child during formative social years, and correcting it carries real psychological benefit alongside the visual benefit. Perfect symmetry is not always achievable. Some under- or over-correction is common. A second procedure is not a failure of the first — it’s part of how strabismus is managed in a proportion of patients. Strabismus surgery is often iterative. That is completely normal and should be explained before the first operation, not discovered afterward.

For adults having surgery for longstanding strabismus, the situation is different. The amblyopia cannot be reversed in adulthood, and the realistic goal is cosmetic alignment and, where possible, the elimination of double vision. Many adults who had a squint as a child and are finally addressing it in their thirties or forties have outcomes they find transformative in terms of confidence and social ease.

Seek Prompt Assessment If

A child of any age develops a new squint, even if it seems to come and go
An adult develops sudden new double vision or a visible eye turn that was not present before
A child has a white pupil reflex in photographs instead of the normal red reflex
A child with known strabismus seems to be developing a strong preference for one eye

A new squint in a child always needs assessment, not observation. In a small number of cases it is the presenting sign of a serious underlying condition including retinoblastoma, which is why any new squint with an abnormal red reflex is a same-day referral. A sudden new squint in an adult with diplopia needs neurological investigation urgently, as it can indicate a cranial nerve palsy from a structural cause.

Frequently Asked Questions About Strabismus

Will my child grow out of their squint?
Pseudostrabismus — where wide nasal skin folds make the eyes appear crossed when they’re actually straight — does resolve as the face matures. Real strabismus does not. A child with a genuine eye turn will not grow out of it, and watching and waiting is not neutral: every month of untreated strabismus during the critical period of visual development carries a cost in terms of amblyopia risk. If you are unsure whether the squint is real, get it assessed. An orthoptist can make that determination quickly.
Does wearing glasses really fix a squint?
For accommodative esotropia, yes, sometimes completely. The squint is driven by the effort of focusing through an uncorrected long-sighted prescription. Give the eye the right glasses, remove the need for that extra focusing effort, and the convergence reduces or disappears. This only works for the accommodative component of the squint. If there is a structural or non-accommodative component as well, surgery will still be needed for the residual deviation after the glasses have done their part.
My child had surgery but the squint is coming back. Is this normal?
Regression after strabismus surgery is real and relatively common, particularly in the first few years. The eye muscles adapt over time and the deviation can drift back. This is not a sign the surgery failed. It’s how strabismus works in a proportion of cases. Many patients have two or more procedures over their lifetime and achieve excellent long-term alignment. Regular follow-up after surgery is needed precisely to catch regression early.
I had a squint as a child that was never treated. Can anything be done now?
Yes, though the goals are different from treating it in childhood. The amblyopia from untreated childhood strabismus cannot be fully reversed in adulthood. But the alignment can be corrected surgically, the double vision can be addressed with prisms or surgery, and the cosmetic and psychological impact of having straight eyes for the first time is something many adults describe as genuinely life-changing. Age is not a barrier to strabismus surgery.
Could my child’s squint be something serious?
The vast majority of childhood strabismus is benign and related to refractive error or idiopathic muscle imbalance. A small proportion is associated with more significant conditions: retinoblastoma can present as a squint, as can intracranial tumours or other neurological causes. This is why any new squint in a child should be assessed promptly rather than observed. The examination takes minutes and provides reassurance in most cases. The cases where something serious is found are exactly why prompt assessment matters — and equally, why most parents leave the clinic reassured.
Will my child need glasses after surgery?
If they needed glasses before surgery for a refractive error, they will almost certainly still need them afterward. Surgery moves the eyes to a new position; it does not change the optics of the eye. A child with accommodative esotropia who had surgery for a residual deviation after glasses still needs those glasses to maintain the alignment the surgery achieved. Taking the glasses off after surgery to see if the eyes stay straight is usually a bad idea and often leads to the squint returning.

If you would like to learn more, the American Optometric Association’s strabismus page and the NCBI StatPearls review on strabismus offer additional information about the condition, its evaluation, and treatment.