ConditionEyes & vision
Strabismus (Crossed or Misaligned Eyes)
Strabismus is a condition in which the eyes do not point in the same direction. One eye may turn in (esotropia, crossed eyes), out (exotropia, wandering eye), up or down, all the time or only sometimes. It affects about 2% to 4% of children and can also start in adulthood. In children, the brain may ignore the turned eye, causing amblyopia (lazy eye) and loss of depth perception. In adults, new strabismus usually causes double vision. Glasses, patching, eye exercises, botulinum toxin and surgery can realign the eyes.
Also called: Crossed eyes, squint, wandering eye, eye misalignment, esotropia, exotropia
At a glance
- What it is
- The eyes are not aligned; one turns in, out, up or down.
- Children
- Risk of amblyopia (lazy eye) and poor depth perception; early treatment matters.
- Adults
- Usually causes double vision; may signal a nerve, muscle or thyroid problem.
- Diagnosis
- Eye exam with cover tests, prism measurements and a dilated exam.
- Treatment
- Glasses, patching or drops for amblyopia, prisms, botulinum toxin, eye muscle surgery.
When to get help
Call 911 or go to the ER
- Sudden eye misalignment or double vision with headache, drooping eyelid, a large pupil, weakness, numbness or speech trouble (possible aneurysm or stroke)
- Eye misalignment after a head injury
See a doctor within a day or two
- New eye turn in an adult or older child, especially with double vision
- A child whose eye turn appears suddenly, or with a white pupil in photos, headache or vomiting
- A child with an eye turn who has a family history of eye cancer
Book a routine appointment
- An eye that drifts in or out after 4 months of age, even occasionally
- A child who tilts their head, closes one eye in sunlight, or bumps into things
- Long-standing eye turn in an adult who wants treatment
Usually safe to manage at home
- Occasional eye wandering in a baby under 4 months old (this is often normal)
Types of strabismus
| Type | Direction | Notes |
|---|---|---|
| Esotropia | Eye turns in | Infantile esotropia appears before 6 months; accommodative esotropia linked to farsightedness, often age 2 to 3 |
| Exotropia | Eye turns out | Often intermittent, noticed when tired or looking far away |
| Hypertropia / hypotropia | Eye turns up or down | Often from fourth nerve palsy or muscle problems |
| Pseudostrabismus | Appears crossed but is not | Wide nasal bridge or skin folds in babies; normal eye alignment on testing |
Strabismus may be constant or intermittent, and may involve one eye or alternate between eyes.
Causes
In children
- refractive errors, especially significant farsightedness (accommodative esotropia)
- family history
- premature birth and low birth weight
- conditions such as cerebral palsy, Down syndrome and hydrocephalus
- poor vision in one eye, for example from cataract or rarely retinoblastoma
- often no clear cause
In adults
- cranial nerve palsy from diabetes, high blood pressure, head injury, tumors or aneurysm. See cranial nerve palsy
- thyroid eye disease
- myasthenia gravis
- stroke
- decompensation of a childhood strabismus
- after eye surgery, such as retinal or cataract surgery
- age-related changes in eye muscle supports ("sagging eye syndrome")
Symptoms
- an eye that visibly turns in, out, up or down
- double vision, especially in adults
- squinting or closing one eye, particularly in bright light
- head tilting or turning
- eye strain, headaches
- poor depth perception
Children often have no symptoms because the brain suppresses the image from the turned eye.
Strabismus and lazy eye
Amblyopia (lazy eye) is reduced vision in one eye because the brain did not develop normal connections with that eye during childhood. Strabismus is a common cause, because the brain ignores the misaligned eye. Amblyopia is most treatable before age 7 to 8, which is why early detection of strabismus matters.
Diagnosis
An eye doctor (ophthalmologist or optometrist) will:
- check vision in each eye
- perform cover tests to detect and measure misalignment
- measure the deviation with prisms
- test eye movements in all directions
- check focusing and prescribe glasses after dilating drops
- examine the inside of the eye
- arrange brain imaging or blood tests for new adult strabismus with neurological signs
Treatment
- glasses: can fully correct accommodative esotropia
- amblyopia treatment: patching the stronger eye or atropine drops to make the weaker eye work
- prism glasses: for small deviations and double vision in adults
- eye exercises: effective mainly for convergence insufficiency (difficulty focusing at near)
- botulinum toxin injections: weaken an overacting muscle; used in some children and adults
- strabismus surgery: tightens or repositions eye muscles; usually a day procedure; adjustable sutures may be used in adults
Surgery in adults is not only cosmetic: it can relieve double vision, improve depth perception and widen the field of vision.
Outlook
With early treatment, most children achieve good alignment and vision, though some need more than one surgery or long-term glasses. Adults with strabismus can usually be helped at any age. Treatment of the underlying cause in new adult strabismus is essential.
Frequently asked questions
What is the difference between strabismus and lazy eye?
Strabismus is a misalignment of the eyes. Lazy eye (amblyopia) is reduced vision in one eye due to abnormal visual development. Strabismus can cause amblyopia in children because the brain ignores the turned eye, but they are separate conditions.
Can strabismus be fixed in adults?
Yes. Adults can be treated with prism glasses, botulinum toxin or eye muscle surgery, which can relieve double vision and improve appearance and depth perception. New strabismus in adults also needs evaluation for an underlying cause.
Is it normal for a baby's eyes to cross?
Occasional crossing or wandering is common in the first 3 to 4 months while eye coordination develops. Constant crossing at any age, or any misalignment after 4 months, should be checked by an eye doctor.
Does strabismus surgery hurt?
The surgery is done under anesthesia. Afterward, the eye is usually sore, red and scratchy for a few days to a couple of weeks. Most people return to normal activities within a week.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Ophthalmology: Strabismus; Esotropia and exotropia Preferred Practice Pattern
- American Association for Pediatric Ophthalmology and Strabismus: Strabismus
- National Eye Institute: Amblyopia (lazy eye)
- MedlinePlus: Strabismus
- NHS: Squint