Amblyopia, sometimes called Lazy eye, is a common and sometimes severe defect of vision in one or both eyes. It occurs as a developmental fault in small children when, for any reason, they are prevented from forming sharp images in the centre of their retinas in early life. Amblyopia, has many causes. Most often it results from either a misalignment of a child's eyes, such as a squint (strabismus), or a difference in refractive power of the two eyes. The brain chooses the eye that is easier to use and develops a preference for this eye only. If the condition persists, the weaker eye will never develop good vision and may even become functionally blind.

Amblyopia is treated under the guidance of an eye specialist (ophthalmologist), but practical day-to-day management is by specialists called orthoptists. Orthoptists are concerned mainly with managing squint in childhood and avoiding the amblyopia that results from a squint.

Causes

For the development of normal vision it is essential that clear visual images be formed on the retinas during infancy and childhood, so that normal nerve impulses pass back from the eyes to the brain. If this does not happen, normal vision will not develop. It is the passage of normal nerve impulses from the eyes to the brain that brings about the permanent connections for normal vision. These links can be made only before the age of seven or eight. After that, no further development is possible; if amblyopia is present after that age it will be permanent and cannot be cured. This is why early diagnosis and treatment is important.