What Is Strabismus? 

Causes Of Strabismus Or Crossed Eyes

What is strabismus? Strabismus is what most people call "crossed eyes" or "cross eyes." It may also be called tropia. Non-medical names for strabismus include eye turns, wall-eyes, wandering eyes, and deviating eye. When someone has strabismus, the eyes appears to turn in separate directions or "cross" when the person is looking at something. 

Causes of a strabismus are unclear, but genetics may play a role. Many people are surprised to find out that this condition is not caused by a muscle or nerve problem, but occurs instead in the control system of the brain.

People often wonder what a person with a strabismus actually sees when they look at something. There are three possibilities:

1. double vision will occur because the eyes are not aimed at the same target.
2. the brain automatically suppresses images from one of the eyes so the person sees only one image, just as other people do.
3. the brain can compensate, fusing the two separate images into one. This phenomenon is known as anomalous retinal correspondence, and it generally develops before the age of four. It is extremely rare if the strabismus develops after age four.

Strabismus and amblyopia Strabismus is not the same thing as "lazy eye" or amblyopia, which is covered separately on this website. Click on lazy eye.

Strabismus types There are a number of different strabismus types. The most common and best known types include:

Constant Strabismus: when the eye turn occurs all of the time

Intermittent Strabismus: the eye turn occurs only some of the time or in certain situations (such as stress).

Esotropia: the classic "cross eyed" condition in which one or both eyes turn inward toward the nose
 
Infantile Esotropia: a specific sub-type of esotropia which begins early in life, often between 3 and 6 months. It is not known at this time if congenital factors are among the causes.

Congenital Esotropia: a traditional name for infantile esotropia.

Hypertropia: A tendency of one eye to deviate upward.

Duane's Syndrome: also known as DS, in which the eye is unable to turn out. DS) is a rare eye problem.

Correcting strabismus When a strabismus occurs after age six, correcting it is difficult. Because of this, early detection is important and ophthalmologists recommend that every child should have their first eye exam before their first birthday. Age nine months is recommended most often.

Intermittent strabismus usually doesn't require aggressive treatment, but monitoring is still a good idea.

At the discretion of a doctor, certain types of eyeglasses may be help in correcting strabismus, as may an eye patch. Meanwhile, it's important to involve infants and toddlers in activities that will help them develop hand-eye coordination. These tasks help speed up treatment and contribute to a positive outcome.

Eye surgery for strabismus Surgery is just one of the possible treatment options for strabismus. Non-surgical treatment is available and is actually more likely to result in better vision. Eye surgery for strabismus involves cutting or moving the eye muscles, which doesn't necessarily change the brain or the signals it sends to these muscles. In other words, eye surgery for strabismus can improve cosmetic appearance, it does not necessarily improve eyesight or vision.