What is "lazy eye"?
"Lazy eye", or amblyopia, is caused by low vision in one or both eyes due to lack of use during a child’s visual development (approx. before the age of eight). It is a disorder that originates in childhood, but can continue into adulthood, if it is not diagnosed and treated early.
What causes it?
The main causes are:
- Strabismus: when the eyes are misaligned and point in different directions, the child’s brain, which has a great ability to adapt, suppresses vision in one eye to counter the abnormality and prevent double vision.
- Refractive error: when a child has hyperopia, astigmatism or myopia, the image that reaches the brain lacks sharpness, resulting in the brain selecting the vision of the eye with less refractive error.
- Cataracts, ptosis (drooping eyelid), retinal diseases: other diseases that interfere with the proper development of vision in children.
How can it be prevented?
All children should undergo an ophthalmic examination to detect for amblyopia before the age of three. Early diagnosis is vital to ensure that "lazy eye" is treated properly and to prevent the condition from continuing into adulthood.
A paediatric ophthalmologist can perform an examination to detect for this disorder at any age, however small and uncooperative the child.
Parents, teachers or caregivers may suspect that the child has abnormal vision in the following types of circumstances:
- Family members cannot easily be identified over long distances.
- Objects need to be held close to the eyes.
- One eye deviates.
- In most cases, as the child can see well with the good eye, normal development occurs, with the amblyopia remaining present until a routine eye test by a paediatrician, optician or ophthalmologist detects the problem.
Treatment involves correcting the cause of amblyopia (strabismus, refractive error, drooping eyelid, etc.) and, at the same time, forcing the lazy eye to work, at the expense of the good eye. The best and fastest way of achieving this is by patching the healthy eye over a period of time, the length of which is determined by the degree of amblyopia and the age of the child.
Other methods of penalising the healthy eye include the use of dilating eye drops to cause blurred vision or prescription glasses that are unnecessary for the good eye.