Amblyopia (Lazy Eye) - Causes, Eye Conditions, Symptoms, Types, Diagnosis, Treatment, Prevention

Learn about Amblyopia (lazy eye), a vision problem that usually affects children but can occur in adults. Discover its causes, symptoms, types, diagnosis, treatment, and prevention methods.

Amblyopia, commonly known as a “lazy eye,” is a vision problem that usually affects children but can also occur in adults. It is a condition in which one or both eyes do not develop normal vision during early childhood, even with the use of glasses or contact lenses. 

In this article, we will discuss the causes, symptoms, types, diagnosis, treatment, and prevention of Amblyopia.

Causes of Amblyopia

Amblyopia can occur when the brain favours one eye over the other. This can happen if one eye has a much stronger prescription than the other, if one eye is misaligned or if there is a problem with one eye that prevents it from focusing correctly. If the brain relies too heavily on one eye, the other eye will not develop normal vision. Note: amblyopia can sometimes affect both eyes.

Other factors that can contribute to Amblyopia include:

• Family history of Amblyopia.
  
  
• Premature birth or low birth weight.
  
  
• Eye injury or infection.
  
  
• Prolonged eye patching at a young age.
  
  

Risk factors of Amblyopia

• Family History: Having a family member with amblyopia, strabismus, or other eye conditions can increase the risk.
  
  
• Premature Birth: Babies born prematurely or with low birth weight are more likely to develop amblyopia.
  
  
• Developmental Delays: Children with developmental delays or disorders are at a higher risk.
  
  
• Refractive Errors: Significant differences in focus between the two eyes (anisometropia) can lead to amblyopia.
  
  
• Eye Conditions: Conditions like cataracts, ptosis, or severe eye injuries can contribute to amblyopia.
  
  

What eye conditions may lead to amblyopia?

Amblyopia can be caused by various eye conditions that affect the normal development of vision during childhood. Here are some common eye conditions that may lead to amblyopia:

• Strabismus – This is a condition where the eyes are misaligned and do not work together properly. One eye may turn inward, outward, upward, or downward, while the other eye looks straight ahead.
  
  
• Refractive errors – Near-sightedness (myopia), farsightedness (hyperopia), or astigmatism can cause amblyopia in one or both eyes if left uncorrected.
  
  
• Cataracts – A cataract is a clouding of the eye’’s natural lens, which can cause blurry or cloudy vision.
  
  
• Ptosis – This is a drooping of the upper eyelid that can partially or completely cover the eye, causing amblyopia.
  
  
• Anisometropia – This is a condition where there is a significant difference in refractive error between the two eyes. The brain may favour the eye with the less severe refractive error, causing amblyopia in the other eye.

It is important to note that amblyopia can occur even if the eye condition causing it is successfully treated. This is because the brain may have already learned to ignore the vision in the affected eye. Regular eye exams during childhood are essential for early detection and treatment of any eye conditions that may lead to amblyopia.

Signs and Symptoms of Amblyopia

Here are some common signs and symptoms of amblyopia:

• Reduced visual acuity in one eye – The affected eye will have poor vision compared to the other eye. This can be detected during a routine eye exam.
  
  
• Poor depth perception – Amblyopia can affect depth perception, which is the ability to judge the distance between objects.
  
  
• Squinting or shutting one eye – Children with amblyopia may close one eye or squint in order to see better.
  
  
• Abnormal eye movements – The affected eye may not move in sync with the other eye.
  
  
• Head tilting – Children with amblyopia may tilt their head to one side in order to see better.
  
  

It’s important to note that in many cases, amblyopia may not show any symptoms, and a child may not even be aware that they have the condition. This is why it is important to have regular eye exams, especially during childhood.

Types of Amblyopia

There are three main types of Amblyopia:

Strabismic Amblyopia

Strabismic Amblyopia occurs when one eye is misaligned or turns in a different direction than the other eye. The misaligned eye may become suppressed, and the brain will rely on the other eye, causing the misaligned eye to lose vision over time.

Refractive Amblyopia

Refractive Amblyopia occurs when there is a focusing error in one or both eyes, leading to blurred image on the retina and poor visual signal travelling to the brain.

Deprivation Amblyopia

Deprivation Amblyopia occurs when there is a problem with one eye that prevents it from receiving images from the outside world. This can be caused by a congenital cataract, a droopy eyelid, or another condition that prevents light from entering the eye.

Diagnosis of Amblyopia

Amblyopia can be diagnosed through a comprehensive eye exam by an optometrist or ophthalmologist. The following tests and procedures may be used to diagnose amblyopia:

• Visual acuity test – This test measures the clarity of vision in each eye. The optometrist or ophthalmologist may use an eye chart or a specialised device to assess visual acuity in children.
  
  
• Refraction test – This test determines if there are any refractive errors such as nearsightedness, farsightedness, or astigmatism that may be causing amblyopia. Drops may be required to paralyse the child’s focus and accommodation, to more accurately determine the degree of refractive error.
  
  
• Ocular motility test – This test checks to see if the eyes are aligned, and working together.
  
  

Treatment of Amblyopia

If amblyopia is diagnosed, the earlier it is detected and treated, the better the chances of successful treatment

Treatment options for Amblyopia include:

Glasses

In some cases, prescribing and wearing the correct glasses will treat the amblyopia. 

Patching

Patching involves placing a patch over the stronger eye to force the weaker eye to work harder. This treatment can help the brain to develop stronger connections with the weaker eye, leading to better vision over time. A patch may be placed over the skin or on top of the glasses frame. 

Atropine Eye Drops

Atropine eye drops can be used to blur the vision in the stronger eye, forcing the weaker eye to work harder. This treatment can be an alternative to patching for some children who have difficulty wearing an eye patch.

Prevention of Amblyopia

•  Early detection and treatment are key to preventing Amblyopia. All children should have their vision screened at pre-school age, around 4 – 5 years.
  
  
• Correcting Vision Problems: If a child has a vision problem, such as near-sightedness, farsightedness, or astigmatism, correcting it with eyeglasses or contact lenses can help prevent amblyopia.
  
  
• Treating Strabismus: Strabismus is a condition where the eyes are misaligned and point in different directions. If left untreated, it can cause amblyopia. Treatment may include glasses, patching, or surgery.
  
  

When to See a Doctor

• Routine Eye Exams: Children should have their vision screened at regular intervals, especially at pre-school age (around 4-5 years).
  
  
• Noticeable Symptoms: If you notice any signs of amblyopia in your child, such as squinting, head tilting, or abnormal eye movements, schedule an appointment with an eye doctor.
  
  
• Family History: If there is a family history of amblyopia or other eye conditions, it is important to have your child’s eyes examined early and regularly.
  
  
• Developmental Concerns: If your child has developmental delays or disorders, consult with an eye doctor to rule out or address any vision problems.
  
  

How to take care of a child with amblyopia?

If your child has been diagnosed with amblyopia, there are several ways you can help them manage their condition:

• Encourage Regular Eye Exams: Regular eye exams are crucial for children with amblyopia. Your child’s eye doctor will monitor their vision and make any necessary adjustments to their treatment plan.
  
  
• Ensure They Wear Their Glasses or Contacts: If your child has a vision problem, such as near-sightedness, farsightedness, or astigmatism, ensure they wear their glasses or contact lenses as prescribed. This can help prevent further vision loss in the weaker eye.
  
  
• Help Them With Patching Therapy: If your child is undergoing patching therapy, help them wear the patch as prescribed. Encourage them to participate in activities that don’t require fine visual skills, such as listening to music or playing board games.
  
  

Be Supportive: Amblyopia can be frustrating and challenging for your child. Be patient and supportive, and encourage them to persevere with their treatment plan.

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