Amblyopia, often known as ‘lazy eye’, is an early childhood condition where the child’s vision does not develop properly. It usually occurs in one eye, but it can occur in both eyes. Amblyopia affects approximately 2% of children.
Most commonly amblyopia occurs as the result of a squint (strabismic amblyopia) or because the two have have different refractive errors (anisometropic amblyopia). The latter can lead to poor vision in the absence of a noticeable squint and may not be detected unless vision is specifically tested for each eye.
Babies are is able to see as soon as they are born, and vision continues to develop until around seven or eight years of age. Treatment to improve the vision in an eye, which is lazy or amblyopic is usually effective until about seven years of age and is a combination of glasses, patching or atropine eyedrops. A patch will cover the good or straight eye to ensure that the child uses their poor eye and will allow the vision to improve. The patch is usually used with any prescribed glasses.
For best results, the child should be carrying out detailed work such as reading, writing, drawing, puzzles, computer games, etc., when wearing the patch.
How does a patch affect the squint?
Patching purely improves vision by making the brain use the amblyopic eye. The unpatched eye will appear to be straight while the patch is worn. Sometimes when the patch is removed the squint may be temporarily more noticeable, but later returns to the pre-patching position.
Will my child need to wear a patch?
Possibly, if your child is less than about eight years and if the vision in one eye is reduced because of the squint. This will mean regular follow up visits.
Which eye does the patch need to be put on?
On the straight eye or the better eye so that the eye with the poorer vision is used on its own for some part every day. It is a very effective way of improving vision.
Does my child wear his glasses with the patch?
Yes, the patch should be worn on the face. It is made from non-irritating material to prevent rashes. Spectacles are worn over the patch.
How long should the patch be worn?
This varies according to the child’s need and may be from less than one hour to a day to all day. Detailed work activities such as colouring, reading or schoolwork should be undertaken during patching. It can be useful to negotiate this with your child’s teacher. It is important that the child is involved in some near vision activity during patching. This will achieve maximum effect and help the child comply with patching because it distracts attention from the patch. Perseverance with patching is vital.
Another way of getting a lazy eye to work is putting atropine into the good eye to blur the vision and make the weaker eye work harder.
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 consultant.
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 consultant 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 that, the eyes and the brain became too mature to change. Later attempt to treat are difficult and might not be successful.