Amblyopia (lazy eye)
Amblyopia develops in childhood and results in reduced vision in one eye.
What is amblyopia?
Amblyopia happens when one eye is used less than the other from birth to seven years of age, which leads the brain to prefer the better eye. Rarely, as a result of a strong glasses prescription, amblyopia may affect both eyes.
What causes amblyopia?
Amblyopia can be caused by:
• A turn in the eye (a strabismus or squint)
• A difference in the glasses prescription between the two eyes
• An obstacle blocking visual stimulation to the eye, such as a droopy eyelid or cataract (cloudy lens); the amblyopia might persist even after the obstacle has been removed
Treatments for amblyopia
Glasses can help and should be worn full-time. A patch covering the good eye will stimulate the weaker eye. The length of time the patch needs to be worn depends on how bad the vision is and on the age of the child. If glasses are worn, the patch should be worn under the glasses, but sometimes, when the vision has started to improve, the patch can be worn on the glasses. In some cases, particularly if the child cannot wear a patch, special eye drops can be used to blur the vision in the good eye.
Most cases of amblyopia are treatable. However, the success of treatment is dependent on the initial level of vision your child has in the bad eye, their age and the level of co-operation with treatment. It is very important to detect and treat amblyopia as early as possible to get the best possible vision. If it is not treated, the vision in that eye will be permanently impaired, so it very important that you try really hard to follow the instructions given by your child’s doctor or orthoptist.
We know that children do not always understand why they need to cover their good eye and treatment can be difficult. Give lots of praise when the patch is worn well and be ready to distract your child’s attention to prevent the patch being pulled off. Your orthoptist is very experienced in dealing with children who have amblyopia and can advise you about carrying out the treatment at home as effectively as possible.
Amblyopia is most successfully treated before seven years of age. After this, the eyes and brain become too mature to change. Later attempts to treat are difficult and might not be successful.