An infantile esotropia is a convergent strabismus, which develops within the first 6 months of life. It is also known as congenital esotropia. The exact cause of infantile esotropia is unknown, but it is thought to be due to a failure of the eye movement control mechanisms in the brain to develop properly. Children are more likely to develop infantile esotropia if they have a family history of strabismus, were born prematurely, have developmental delay, a seizure disorder or hydrocephalus. However, the vast majority of children with infantile esotropia have no family history of strabismus and have no other related medical conditions.
The features of infantile esotropia include:
A large angle convergent strabismus
Children will often choose to use their left eye to look at objects to their right and their right eye to look at objects to their left. This is known as cross fixation. For this reason it often appears that children are not able to move their eyes outwards, even though they can.
Equal vision in both eyes
Although before treatment children with infantile esotropia do not use both eyes together, the majority are happy to swap from one eye to the other. Because they tend to use both eyes equally (just not at the same time) they usually develop equal vision in both eyes. Children with other types of convergent strabismus frequently prefer to use one eye more than another and are at higher risk of developing amblyopia (a lazy eye).
Mild degree of long sightedness
The majority of children under 1 year of age are moderately longsighted, but do not require glasses. However some children with infantile esotropia may be more long sighted than is normal and will require glasses. Wearing these longsighted glasses can sometimes reduce the size of the inward turn.
Upward drift of the eyes
An upward movement of the eye (s) when the child looks to the opposite side is often seen in children with infantile esotropia. This is caused by an overaction of a muscle called the inferior oblique muscle.
Occasionally one eye can have a tendency to spontaneously drift upwards. This is called dissociated vertical deviation, DVD for short. DVD is not normally present before the age of 2-3 years.
It is quite common for inferior oblique overaction and DVD to occur together.
The medical term for wobbly eyes is nystagmus. Some children with infantile esotropia have a mild form of nystagmus, which is only apparent when one of their eyes is covered or closed. This is called latent nystagmus.
The aims of treatment are:
- To realign the eyes and in so doing try and restore some form of stereopsis (3D vision).
- To ensure the child develops equal vision in both eyes.
Republished, with permission, from www.squintclinic.com.