Strabismus (Eye Misalignment)

Strabismus is a condition in which the eyes don't line up properly. One eye may turn inward, outward, upward, or downward while the other eye looks straight ahead. It can be constant or intermittent, and affects both children and adults differently.

For adults with persistent eye misalignment or stable double vision, an adult strabismus surgery evaluation can assess whether surgery is appropriate.

Types of Strabismus

By Direction

Esotropia (eye turns inward)

• Most common type in children
• May be present at birth or develop later
• "Cross-eyed" appearance

Exotropia (eye turns outward)

• May be constant or intermittent
• Often worse when tired or daydreaming
• "Wall-eyed" appearance

Hypertropia (eye turns upward)

• Often caused by cranial nerve problems
• May indicate fourth nerve palsy

Hypotropia (eye turns downward)

• Less common
• May be associated with orbital or muscle problems

By Pattern

Constant: Always present Intermittent: Comes and goes Alternating: Switches between eyes

Causes

In Children

• Congenital/Infantile: Present from birth
• Accommodative: Related to focusing effort
• Refractive errors: Uncorrected farsightedness
• Developmental: Unknown cause

In Adults

New-onset strabismus in adults usually has an identifiable cause:

• Cranial nerve palsies: Third, fourth, or sixth nerve
• Thyroid eye disease
• Myasthenia gravis
• Stroke or brain tumor
• Trauma
• Decompensated childhood strabismus

Symptoms

In Children

• Visible eye misalignment
• Squinting or closing one eye
• Head tilting or turning
• Poor depth perception
• May be unaware of any problem

In Adults

• Double vision (diplopia)
• Eye strain or fatigue
• Difficulty reading
• Problems with depth perception
• May tilt or turn head to reduce diplopia

Why It Matters

Children

When eyes don't align, the brain receives two different images. In children, the brain may "turn off" one eye to avoid confusion, leading to amblyopia. This can cause permanent vision loss if not treated during the critical period of visual development.

Adults

The adult brain usually cannot reliably suppress a new misalignment, so adults commonly develop double vision. This can significantly impact daily activities, work, and driving.

Diagnosis

Eye Examination

• Visual acuity testing
• Cover tests (cover-uncover, alternate cover)
• Prism cover test
• Eye movement examination
• Hess chart testing to map incomitant eye-movement weakness when indicated
• Worth four-dot testing to assess fusion and suppression
• Refraction (checking for glasses need)
• Assessment for amblyopia in children

Additional Testing

If new-onset in adults:

• Neurological examination
• MRI brain/orbits
• Blood tests (thyroid, myasthenia)
• May need eye movement examination

Treatment

Glasses

• Correct refractive errors
• Bifocals for accommodative esotropia
• Prism glasses to reduce diplopia

Patching/Occlusion

• For amblyopia in children
• Occlusion therapy
• Encourages use of the weaker eye under a prescribed schedule; treating amblyopia does not necessarily straighten the eye

Botulinum Toxin

• Botox injection to eye muscles
• Temporary effect
• May be diagnostic or therapeutic

Surgery

• Strabismus surgery
• Adjusts the position of eye muscles
• May need more than one procedure
• The degree of alignment and double-vision improvement varies

Vision Therapy

• Eye exercises
• For specific types of strabismus
• See Vision Therapy

When to Seek Care

Prognosis

Children

• Treatment aims to support vision development and improve alignment
• The plan depends on the type of strabismus and whether amblyopia is present
• Glasses, amblyopia treatment, and follow-up may still be needed after surgery
• Some children need more than one operation

Adults

• The outlook depends on the cause, previous treatment, and ability to use both eyes together
• Surgery can improve eye position; prisms can help some people manage double vision
• Improved alignment does not guarantee single vision
• Residual or recurrent misalignment may require further treatment

AAPOS adult strabismus guidance describes potential benefits alongside persistent double vision, incomplete alignment, and the possibility of another operation.

Frequently Asked Questions

Can strabismus be cured?

Treatment can improve alignment and help manage double vision, but the result depends on the cause and how the eyes work together. Children may also need glasses or amblyopia treatment. Some adults continue to need prisms or further surgery; improved alignment does not guarantee single vision.

Is strabismus surgery safe?

Yes, strabismus surgery has a strong safety record. It's performed on the outside of the eye (not inside), but serious complications are still possible.

Can strabismus come back after surgery?

Sometimes, especially in children who are still growing. Some patients need more than one surgery over time.

Does everyone with strabismus need surgery?

No. Many cases can be managed with glasses, prisms, or in some cases just observation. Surgery is recommended when other treatments aren't sufficient.

References

1. American Academy of Ophthalmology. What Is Strabismus?.
2. American Association for Pediatric Ophthalmology and Strabismus. Strabismus.
3. American Association for Pediatric Ophthalmology and Strabismus. Adult Strabismus (Adult Eye Misalignment).