Amblyopia

Amblyopia, or lazy eye, is a disorder of sight in which the brain fails to process inputs from one eye and over time favors the other eye. It results in decreased vision in an eye that otherwise typically appears normal. This condition results from failure of growth of optic nerve during infancy and early childhood due to brain's preference of one eye over the other. It's more common in children, and most cases are treatable, however if untreated, may lead to gradual or acute loss of vision.

Although amblyopia affects one eye, it can affect both eyes together, and sometimes may be obvious without any ophthalmological examination.

Early diagnosis and treatment of amblyopia can help to its long-term effect on child's vision, and usually the affected eye can be treated by glasses or contact lenses or eye patch.

How to know if your child is affected by amblyopia?

If you notice the following:

• Abnormal eye movement vertically and horizontally.
• Asymmetric direction of both eyes when looking at objects.
• One of both eyes directed inside or outside away from the center.
• Persistent red eye.
• Ptosis of the affected eyelid, which interferes with vision.
• Inability to continuously follow objects in his visual field after 3 months of age.
• The child bending his head toward the object he is trying to focus on.

Complete eye examination is advised for children 3 – 5 years old.

Causes:

Amblyopia occurs due to abnormal vision in early life, which leads to alteration of visual pathways from retina of the eye to the brain, so the affected eye receives less visual signals, and eventually, both eyes lose their ability to work simultaneously, and the brain inhibits signals that come from the affected eye.

Anything blurs the vision, Esotropia or Exotropia can result in amblyopia. The most common causes of this condition are:

• Muscle imbalance "strabismic amblyopia": most common cause of amblyopia is the imbalance of the muscles that direct both eyes, this imbalance can lead to eye deviation inside or outside, which prevents both eyes from working together.
• The difference of visual acuity between both eyes "refractive amblyopia": there is a big difference in prescription of each eye – usually due to hyperopia, but sometimes due to myopia or uneven surface of the eye (astigmatism) - can lead to amblyopia.

Eyeglasses and contact lenses are used usually to correct refractive errors. Some children have amblyopia due to both strabismus and refractive errors.