Amblyopia - The ABCs of Lazy Eye
Introduction to amblyopia
Do you know that amblyopia is one of the leading causes of vision impairment (eyesight problems) in children and adolescents?
If one of your eyes develops good vision while the other does not, the eye with poorer vision is called amblyopic. The condition is common, affecting approximately two or three out of every 100 people. In US alone, amblyopia affects as many as 3% percent of children. The condition leads to poor vision in an otherwise healthy eye due to unequal or abnormal visual input while the brain is developing in infancy and childhood. The condition is sometimes called “lazy eye.” Usually, only one eye is affected by amblyopia, but it is possible for both eyes to be “lazy.”
Amblyopia is poor vision in an eye that did not develop normal sight during early childhood. Hence, the condition usually begins in infancy or childhood.
Causes of amblyopia
Amblyopia can be caused by any condition that affects normal visual development or use of the eyes such as:
What actually happens in amblyopia?
To better understand what occurs in amblyopia, you first need to understand the relationship between your eye and the brain.
You must remember that your brain and the eye work together to produce vision or sight. First, light enters your eye and is then transformed into nerve signals or messages that travel along the optic nerve (the eye nerve) to your brain.
Amblyopia is the medical or clinical term implied when the vision in one of the eyes is decreased or disturbed because the eye and the brain are not working together properly. Apparently, your eye itself “looks” normal, but is not “working” normally because the brain is supporting the remaining eye. As the affected eye is not working, this condition is also sometimes known as “lazy eye”.
Why amblyopia is more common in newborns and children?
The development of equal vision in both eyes is necessary for normal vision. Newborn infants or babies are able to see, but as they use their eyes during the first months of life, their eyesight gradually improves. During early childhood years, the visual system changes quickly and sight continues to develop. If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is normally fully developed and usually cannot be changed.
How is amblyopia diagnosed?
Diagnosis of amblyopia is mainly based on patient’s signs and symptoms, a detailed history and ophthalmologist’s careful examination of the eyes.
In newborns, for example, the ophthalmologist observes the reactions of the baby when one eye is covered. If one eye is amblyopic and the good eye is covered, the baby may attempt to look around the patch, try to pull it off or cry. Your ophthalmologist will also carefully examine the interior of the eye to see if other eye diseases may be causing decreased vision.
Amblyopia treatment in children
To correct amblyopia, a child must be made to use the weak eye. This can be done by the following:
- Patching: A common treatment for amblyopia is to patch the strong eye; the weak eye is strengthened because the child is forced to use it. In other words, patching stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely.
- Drug treatment: A drop of a drug known as atropine is placed in the stronger eye once a day to temporarily blur the vision so that the child will prefer to use the eye with amblyopia. Treatment with atropine also stimulates vision in the weaker eye and helps the part of the brain that manages vision develop more completely.
Amblyopia treatment in adults
Studies on the adult treatment of amblyopia are very limited at this time and scientists don’t know what the success rate might be for treating the same in adults. Treatment in adults, therefore, mainly depends on correcting the underlying cause. For example, if your ophthalmologist finds a cataract or other abnormality, surgery may be required to correct the problem. An intraocular lens may be implanted. Remember, amblyopia cannot usually be cured by treating the cause alone. The weaker eye must be made stronger in order to see normally. Prescribing eyeglasses or performing surgery can correct the cause in some cases.
What can amblyopia lead to?
If left untreated, the amblyopic eye may develop:
- A serious and permanent visual defect
- Depth perception (seeing in three dimensions) may be lost
- If the good eye becomes diseased or injured, a lifetime of poor vision may result
Is early detection and prevention possible?
It is recommended that all children have their vision checked by their pediatrician, family physician or ophthalmologist (eye specialist) at or before their fourth birthday. If the problem is detected and treated early, vision can improve for most children. Amblyopia caused by strabismus or unequal refractive errors may be treated successfully during the first nine years of age. After this time, amblyopia usually does not recur.
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