When one eye develops good eyesight, but the other one doesn’t, the eye with the worse ability to see is called amblyopic. Usually, the disease only affects one eye. In cases when both eyes are “lazy” the condition is called bilateral amblyopia.
The condition is frequent – 2 or 3 of every 100 people have amblyopia. The best time to start treatment is during early childhood, or even better – while the child is still of breastfeeding age.
For eyesight to be normal, it is important that both eyes develop equally. After the first 9 years of life, the visual system is usually fully developed and cannot be changed.
If treatment for amblyopia hasn’t started as soon as possible, a few issues can develop which will affect eyesight in childhood and adulthood.
- The amblyopic eye can develop a serious, permanent vision defect
- Depth perception (3D) can be lost
- If another disease affects the healthy eye, this can mean worse eyesight for the entire life
What is refractive/anisometropic amblyopia?
When the eye focuses light over the retina, a visual image is made. There is a refractive anomaly when the light is not correctly focused in the eyes and images are blurred. When a child has refractive amblyopia, this means that there is a different degree of light bending in each eye. Therefore, the brain uses the eye that can see better and “turn off” perception from the sick one. Firstly, eyes can help by correcting refraction mistakes in both eyes, letting them work together properly.
It is not easy to recognize amblyopia (lazy eye) in children. The child may not be aware that there is a problem. If no visible bending or turning of the eye or other visible condition exists, there is often no way for the parents to notice the problem.
Some symptoms of presbyopia (lazy eye) include:
- Bad eyesight in one eye or overall bad eyesight
- Looking at a specific point, bending the head or closing one eye to focus better
- Bad perception of depth (difficult perception of distance between objects)
- Headache
3 main reasons cause amblyopia:
- Strabismus
- Not the same focus in the 2 eyes and mistakes in refraction of the image (Mistakes in refraction can be corrected with glasses or contact lenses. Amblyopia happens when one of the eyes is not focused, as it is more near-sighted, farsighted or more astigmatic than the other)
- Clouding of clear ocular tissues (eye disease such as cataracts can cause amblyopia. Every factor which makes it more difficult for the image to be focused on the retina in the back part of the eye can cause amblyopia in children. This is often the heaviest form of amblyopia).
Treatment with an eye patch
When there is refractive amblyopia, glasses can be prescribed to fix mistakes in focusing. If glasses do not help improve the child’s eyesight, wearing an eyepatch is necessary for some weeks or months. The “strong” eye of the child is covered with an eyepatch to force them to use the “weaker” eye. Some other ways to achieve that are to blur sight in the strong eye with special eye drops or with glasses with a blurred lens in front of the strong eye.
Amblyopia is usually treated in those ways before surgery to correct the lazy eye, but often treatment with non-invasive methods also continues after surgery.
If your ophthalmologist discovers a cataract or other eye disease, amblyopia may need to be corrected surgically.
The possible eyesight vision is preventable.
Success in treatment of amblyopia also depends on:
- The severity of the disease
- How old the child is when treatment begins
If the problem is discovered on time and treatment begins immediately, the condition improves in most children. Amblyopia caused by strabismus or uneven refractive mistakes can be corrected in the first nine years of life and usually doesn’t show up again.
If amblyopia is not discovered in early childhood, treatment cannot be successful.