Amblyopia vs Strabismus: Causes, Symptoms, and Treatment

Jul 08, 2024 | 5 min read

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Amblyopia and strabismus are common eye conditions with different causes, significantly impacting vision and quality of life. Early diagnosis and treatment are crucial to prevent long-term vision problems and improve outcomes.

amblyopia vs strabismus

What is Amblyopia?

Amblyopia, often called "lazy eye," is a vision development disorder where one eye has reduced vision. This condition typically begins during childhood. It occurs because the brain and the affected eye do not work together correctly. As a result, the brain favors the stronger eye, leading to the weaker eye not developing properly.


Causes of Amblyopia

Amblyopia can be caused by various factors, including:

  • Strabismus: This is when the eyes are misaligned, causing one eye to turn in, out, up, or down. The brain may ignore the input from the misaligned eye to avoid double vision, leading to amblyopia.
  • Refractive errors: Significant differences in the refractive power between the two eyes can cause amblyopia. If one eye is more nearsighted, farsighted, or astigmatic than the other, the brain may rely on the stronger eye, neglecting the weaker one.
  • Deprivation: This occurs when something obstructs vision in one eye, such as cataracts, which prevent clear images from forming. The lack of visual stimulation can cause the eye to become amblyopic.

Symptoms of Amblyopia

Amblyopia symptoms can be subtle, making it challenging to detect without a thorough eye examination. Common signs include:

  • Poor depth perception: Difficulty judging distances accurately.
  • Squinting: Frequent squinting, especially in bright light.
  • Shutting one eye: Tendency to close one eye to see better.
  • Head tilting: Tilting the head to use the stronger eye more effectively.

If you notice any of these symptoms, consult an eye care professional. The American Optometric Association recommends comprehensive eye exams for children at six months and three years. Early detection is vital since the lazy eye won't resolve on its own. Delayed diagnosis into the preteen years or later makes treatment longer and less effective.

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Diagnosing Amblyopia

Diagnosing amblyopia involves a comprehensive eye exam. An eye care professional will conduct various tests to assess visual acuity, eye alignment, and overall eye health. These tests may include:

  • Visual acuity test: Measures how well each eye can see.
  • Cover test: Observes how the eyes move when one is covered.
  • Refraction test: Determines the appropriate lens prescription to correct vision.

Early diagnosis is crucial for effective treatment and preventing long-term vision problems.

Treatment Options for Amblyopia

Treating amblyopia focuses on strengthening the weaker eye and improving the coordination between the brain and the eye. Treatment options include:

  • Corrective eyewear: Glasses or contact lenses can correct refractive errors.
  • Eye patches: Wearing a patch over the stronger eye for a few hours daily encourages the brain to use the weaker eye. A recent publication in the Lancet suggests that starting patching early is more effective than prolonged optical treatment alone.
  • Eyedrops: Temporarily blurring vision in the stronger eye to stimulate the weaker one.
  • Surgery: In severe cases, surgery may be required to remove cataracts or correct other underlying issues.

Early and consistent treatment can significantly improve vision in the affected eye. Regular follow-ups with an eye care professional ensure the treatment is effective and adjusted as needed.

What is Strabismus?

Strabismus, commonly known as "crossed eyes," is a condition where the eyes do not align properly and fail to look at the same place simultaneously. This misalignment can affect one or both eyes, leading to a range of visual problems.

There are several types of strabismus, categorized based on the direction in which the eye turns:

  • Esotropia: The eye turns inward.
  • Exotropia: The eye turns outward.
  • Hypertropia: The eye turns upward.
  • Hypotropia: The eye turns downward.

Each type can vary in severity and frequency, with some cases being constant and others intermittent.

types of strabismus

Causes of Strabismus

Strabismus can arise from various underlying issues, including:

  • Poor eye muscle control: When the muscles around the eyes do not work together properly, it can lead to misalignment.
  • Severe farsightedness: Hyperopia can cause the eyes to strain to focus, leading to crossing or turning.
  • Neurological issues: Conditions affecting the brain can interfere with eye coordination.
  • Injuries: Trauma to the head or eyes can damage the muscles or nerves controlling eye movement.

Symptoms of Strabismus

Identifying strabismus can be straightforward due to the visible misalignment of the eyes. However, other symptoms may include:

  • Double vision: According to the AAO, adults who develop strabismus after childhood often experience double vision, as their brains are accustomed to processing images from both eyes.
  • Headaches: Frequent headaches, especially after visual tasks.
  • Decreased depth perception: Difficulty judging distances and spatial relationships.
  • Misaligned eyes: One or both eyes may turn in different directions.
  • Frequent blinking or squinting: Particularly in bright light.

If you notice any of these symptoms, it is important to consult with an eye care professional for an accurate diagnosis.

Diagnosing Strabismus

Diagnosing strabismus involves a comprehensive eye examination. Key diagnostic methods include:

  • Eye exams: Assess overall vision and eye health.
  • Light reflex testing: Evaluates how light reflects off the eyes to determine alignment.
  • Prism tests: Measures the degree of eye misalignment.
  • Family history analysis: Understanding genetic predispositions that might contribute to the condition.

Early diagnosis is crucial for effective treatment and preventing further complications.

Treatment Options for Strabismus

Treating strabismus aims to align the eyes and improve vision. Treatment options include:

  • Eyeglasses: Corrective lenses can help address refractive errors that contribute to misalignment.
  • Prism lenses: Thicker lenses that help direct light properly, reducing the eye's tendency to turn.
  • Vision therapy: Exercises and activities designed to strengthen eye muscles and improve coordination.
  • Surgery: Surgical intervention to adjust the muscles controlling eye movement, helping to align the eyes.

Regular follow-ups with an eye care professional are essential to monitor progress and adjust treatment as necessary.

Amblyopia vs Strabismus: Key Differences

It is common to confuse amblyopia and strabismus, but understanding their differences is essential. Amblyopia, or lazy eye, results from the brain favoring one eye over the other, leading to reduced vision. Strabismus, on the other hand, involves the physical misalignment of the eyes. Although strabismus can cause amblyopia if untreated, they require different treatment approaches.

The comparison table below highlights the key differences:

Feature Amblyopia Strabismus
Causes brain-eye coordination issues,
refractive errors,
poor muscle control,
neurological issues,
Symptoms poor depth perception,
shutting one eye,
head tilting
misaligned eyes,
double vision,
poor depth perception
Diagnosis comprehensive eye exams,
visual acuity tests
eye exams,
light reflex testing,
prism tests
Treatment corrective eyewear,
eye patches,
atropine drops,
prism lenses,
vision therapy,
eye muscle surgery

If you are unsure about your condition, Docus AI Symptom Checker can help you identify potential vision issues based on the symptoms you or your child are experiencing. While this online tool is useful for initial assessments, it is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with an eye care professional for accurate diagnosis and appropriate treatment.

When to See a Doctor

Early intervention can prevent long-term vision issues and improve treatment outcomes. Here are some key indicators that you or your child should see an eye care professional:

  • Visible Misalignment: If you notice that one or both eyes are not aligned properly, this could be a sign of strabismus. Misalignment can be constant or intermittent.
  • Frequent Squinting or Shutting One Eye: This behavior can indicate amblyopia or difficulty focusing, especially if the child tilts their head to see better.
  • Difficulty Judging Distances: Poor depth perception, such as difficulty catching a ball or frequent tripping, maybe a symptom of a vision problem.
  • Double Vision: Experiencing double vision, particularly in adults who develop strabismus later in life, is a significant indicator that professional help is needed.
  • Headaches and Eye Strain: Persistent headaches or eye strain after reading or other visual tasks can suggest underlying vision issues.

Frequently Asked Questions

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Understanding the differences between amblyopia and strabismus is crucial for effective diagnosis and treatment. Both conditions affect vision but in different ways. Strabismus is a problem with eye alignment, causing the eyes to look in different directions simultaneously. Amblyopia, on the other hand, is a problem with visual acuity where one eye cannot see clearly even with prescription glasses. Importantly, strabismus can be a cause of amblyopia if the misaligned eye is neglected by the brain.

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