A lazy eye, also known by its medical term amblyopia, is a vision condition that occurs in childhood. A lazy eye in children can develop between birth and the age of seven years old, when one eye is used less than the other. As a result, the affected eye is not able to build a strong link with the brain and will have reduced vision.
Typically, amblyopia only affects one eye, although in rare instances, both eyes may be affected due to a strong glasses prescription. It is estimated that this condition affects around 1 in 50 children.
Amblyopia symptoms are not usually noticeable and young children are often unable to identify this vision condition. With young children, you can check their vision by covering one eye at a time. If they are relying on one eye more than the other, they may object to you covering this up. With older children, they may be able to tell you if they’re experiencing issues with their vision.
One eye may appear to be different to the other, but this is typically a symptom of another condition which could contribute to amblyopia in children. These can include an eye squint (strabismus), short-sightedness, long-sightedness or astigmatism.
Often, the signs of a lazy eye are not evident without an eye examination. In the UK, all newborns have their eyes checked a few days after birth and again between the ages of 2-3 months. You can then have regular eye checks at opticians from the ages of 3 years old onwards. If you are worried about any issues with your child’s eyesight, you can consult your GP for a lazy eye test and other examinations.
There are different amblyopia causes, with the most common being a muscle imbalance. Known as strabismus or strabismic amblyopia, this is where an imbalance in the eye muscles results in them crossing and being unable to work in sync with one another.
Refractive amblyopia is where one eye has a significantly reduced sharpness of vision due to differences in prescriptions between the eyes. This is due to vision issues such as long-sightedness, short-sightedness or astigmatism.
When an issue in one eye prohibits a clear field of vision, this can cause deprivation amblyopia. This can be caused by another condition, such as a cataract, and is typically the most severe of the amblyopia types, requiring urgent treatment to prevent a permanent loss of vision in the eye.
A lazy eye occurs when something causes the connection between the brain and the retina in the eye to not develop properly in a child’s early years. This can be a result of other conditions, such as a squint, obstacles in the vision field such as a droopy eyelid or cataract, or differences in prescription between the eyes.
As a result of these potential amblyopia causes, the eye may receive a reduced amount of light, experience a lack of focus or see differences between images in the eyes. As the affected eye receives fewer visual signals, the vision deteriorates and the child becomes more dependent on their stronger eye. If left untreated, central vision in the affected eye may never develop properly.
There are also a number of risk factors associated with the causes of lazy eye, including a family history of amblyopia, premature birth or small size at birth, and developmental disabilities.
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