# Neurological Eye Misalignment: Causes and Treatment

Source page: https://www.kudretgozistanbul.com/en/blog/eye-diseases/neurological-eye-misalignment

**Author:** Kudret Eye İstanbul | **Medical Approval:** Op. Dr. Mehmet Ali Özdil | **Date:** 2026-10-05

> **Summary:** Neurological eye misalignment (nerve-related squint) means the eyes no longer line up because the nerves controlling the eye muscles, or their connections in the brain, have been affected. Unlike childhood squint, it usually starts suddenly in adulthood, with double vision as the most noticeable complaint, and needs a prompt eye examination to find the cause.

## Quick Facts
- **Nerves involved:** The 3rd, 4th and 6th cranial nerves, which control the six muscles moving each eye
- **Most common cause in adults:** Diabetes or high blood pressure affecting the small blood vessels supplying these nerves
- **Diabetes or blood pressure palsies:** Often improve partly or completely within a few months
- **After squint surgery:** Avoid heavy physical activity for 2-3 weeks
- **Emergency signs:** Drooping eyelid, severe headache, difficulty speaking, drooping face or weakness in an arm or leg with sudden double vision or squint

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## What It Is
Each eye is moved by six muscles controlled by three nerves from the brain (the 3rd, 4th and 6th cranial nerves). When one nerve weakens, its muscle cannot work properly, the eyes lose their parallel alignment and a squint appears. It is a nerve-related form of strabismus, named after the affected nerve ("third nerve palsy", "fourth nerve palsy", "sixth nerve palsy"); "palsy" means the nerve is working less than it should.

## Compared With Childhood Squint

| | Childhood squint | Neurological (nerve-related) misalignment |
| :--- | :--- | :--- |
| Onset | Usually in the first years of life, gradually | Usually in adulthood, suddenly |
| Double vision | Usually absent; the brain suppresses the image from the turned eye | Common and noticeable |
| Common causes | Refractive errors (especially long-sightedness), family history, premature birth | Diabetes, high blood pressure, head injury, neurological conditions |
| First approach | Glasses, patching, surgery if needed | Finding the cause, prisms, Botox or surgery if needed |

## Causes
- Poorly controlled diabetes
- High blood pressure
- Head injury
- Conditions affecting the brain's blood vessels, such as stroke
- Neurological diseases such as multiple sclerosis
- Less commonly, a growth in the brain or raised pressure inside the skull

Childhood squint causes (premature birth, a difficult birth, illnesses with high fever, childhood cataract) are different.

## Symptoms
- Double vision that disappears when one eye is covered (the brain cannot merge the two images), making reading, driving or going down stairs difficult
- Loss of the parallel alignment of the eyes
- A drooping eyelid
- Being unable to move the eye in a certain direction
- Tilting or turning the head to reduce double vision

Symptoms depend on the nerve: with the 6th nerve, the eye cannot turn outwards and double vision worsens looking into the distance; with the 3rd nerve, a drooping eyelid and an enlarged pupil may also occur.

## Diagnosis
- The eye doctor examines eye movements, measures the direction and size of the squint, checks in which gaze direction double vision worsens and assesses pupils and eyelids. The tests are not painful.
- Blood sugar and blood pressure checks may be done; if the cause appears neurological, an MRI brain scan or a neurologist's assessment may be requested.
- Adults without symptoms: eye exam every 2 years up to 40, once a year after 40. Babies: an intermittent squint can be normal in the first 3-4 months; one continuing after 6 months of age needs examination.

## Treatment
Planned by age, any loss of vision, the cause and the type of squint. Even if the squint improves on its own, the cause must be investigated and followed up.

### In Adults
- Treating the underlying cause (for example controlling blood sugar and blood pressure)
- Covering one eye to relieve double vision temporarily
- Prism glasses: help merge the images, mostly for smaller squints
- Botox injections into the eye muscles: rebalance them temporarily while recovery is awaited
- Squint surgery: usually once the squint has been stable for several months; avoid heavy physical activity for 2-3 weeks afterwards; temporary double vision in the first days is normal, but see your doctor if it continues

### In Children
Often treated with glasses; with a lazy eye (amblyopia: visual development falling behind because the brain uses that eye's image less), the stronger eye is covered for certain hours a day. Surgery may be needed if the squint continues despite glasses.

## When to Seek Urgent Help
A squint or double vision starting suddenly in adulthood needs an eye doctor without delay. If it comes with a drooping eyelid, severe headache, difficulty speaking, a drooping face or weakness in an arm or leg, go to an emergency department straight away.

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## Frequently Asked Questions

**Q: Does neurological eye misalignment go away on its own?**
A: In some cases. Palsies caused by diabetes or high blood pressure in particular often improve within a few months, but the course depends on the cause, so investigation and follow-up are important.

**Q: Can a squint be a sign of a stroke?**
A: Yes, although uncommon. With difficulty speaking, a drooping face or weakness in an arm or leg, go to an emergency department straight away.

**Q: What causes sudden double vision in adults?**
A: One of the most common causes is damage to the nerves controlling the eye muscles, which diabetes and high blood pressure can affect. Head injuries, neurological conditions and other diseases of the eye muscles can also cause it.

**Q: Can it be corrected with surgery?**
A: If the squint does not improve on its own, surgery can improve alignment and reduce double vision, usually once it has been stable for some time. Avoid heavy physical activity for 2-3 weeks after; temporary double vision in the first days is normal.

**Q: Which doctor treats it?**
A: An eye doctor makes the first assessment; if the cause appears neurological, follow-up is together with a neurologist.

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## References
- American Academy of Ophthalmology (AAO): patient information on double vision and strabismus
- Mayo Clinic: Double vision
- MedlinePlus (U.S. National Library of Medicine): strabismus