Lazy Eye

Ambylopia is also sometimes called a ‘lazy eye’. It is a condition in which the vision in an eye is poor because of lack of use of the eye early in childhood.
The visual loss of ambylopia becomes permanent if not treated before the age of about seven years and then cannot be corrected with the use of glasses.
In order to understand ambylopia it is helpful to understand how vision normally develops.
When a baby is born, although it can see, its visual system is not fully developed. The visual system (eyes and parts of the brain that interpret vision) continues to develop and mature until the age of about 7 years. In order to mature properly, the brain needs signals from the eyes about what they can see. If for any reason a young child does not use one or both of its eyes properly, then vision will not be learnt properly and the child will develop poor vision in the affected eye, ambylopia. Essentially, ambylopia is a developmental problem of the brain rather than the eye itself.

Causes of ambylopia
Squint
A squint is the commonest common cause of ambylopia. When a child has a squint, one eye usually turns up, down, inward or outward. In order to prevent the child from seeing double, the brain ignores the images from the turning eye. As a result of this the visual system related to this eye fails to develop properly and it becomes an amblyopic eye with poor vision.

Other causes of ambylopia
Other common causes of ambylopia include refractive errors (short or long-sightedness, or astigmatism) or congenital problems such as congenital cataract.
These are all problems, which if not treated early can cause visual loss but if treated early and appropriately the visual loss can be miminalised.

How can ambylopia be treated?
The main treatment for ambylopia is to try and encourage the lazy eye to work by restricting the use of the good eye. If this is done early in childhood, the vision can often be brought up to a near normal level, depending on the particular case.
The common way to do this is with ‘patching’. Quite literally, a patch is placed over the better eye for a variable amount of time each day, depending on the severity of the ambylopia and the age of the child.
Treatment is continued until the vision returns to normal or until there is no further improvement. This can be several weeks or several months.