Tropia/Phoria

Strabismus (also known as squint or tropia)

Strabismus is a disorder in which the two eyes do not line up in the same direction, and therefore do not look at the same object at the same time. The condition is more commonly known as "crossed eyes".

Causes

Six different muscles surround each eye and work "as a team" so that both eyes can focus on the same object.

In someone with strabismus, these muscles do not work together. As a result, one eye looks at one object, while the other eye turns in a different direction and is focused on another object.

When this occurs, two different images are sent to the brain -- one from each eye. This confuses the brain. In children, the brain may learn to ignore the image from the weaker eye.

If the strabismus is not treated, the eye that the brain ignores will never see well. This loss of vision is called amblyopia. Another name for amblyopia is "lazy eye." Sometimes amblyopia is present first, and it causes strabismus.

In most children with strabismus, the cause is unknown. In more than half of these cases, the problem is present at or shortly after birth. This is called congenital strabismus.

Most of the time, the problem has to do with muscle control, and not with muscle strength.

Symptoms

Symptoms of strabismus may be present all the time, or may come and go. Symptoms can include:

• Crossed eyes
• Double vision
• Eyes that do not align in the same direction
• Uncoordinated eye movements (eyes do not move together)
• Vision or depth perception loss

It's important to note that because children can develop amblyopia so quickly, they may never have double vision.

Treatment

The first step in treating strabismus in children is to prescribe glasses, if needed.

Amblyopia or lazy eye must be treated first. A patch is placed over the better eye. This forces the weaker eye to work harder.

Your child may not like wearing a patch or eyeglasses. A patch forces the child to see through the weaker eye at first. However, it is very important to use the patch or eyeglasses as directed.

If the eyes still do not move correctly, eye muscle surgery may be needed. Different muscles in the eye will be made stronger or weaker.

Eye muscle repair surgery does not fix the poor vision of a lazy eye. A child may have to wear glasses after surgery. In general, the younger a child is when the surgery is done, the better the result.

Adults with mild strabismus that comes and goes may do well with glasses and eye muscle exercises to help keep the eyes straight.

More severe forms of adult strabismus will need surgery to straighten the eyes. If strabismus has occurred because of vision loss, the vision loss will need to be corrected before strabismus surgery can be successful.

Source: U.S. National Library of Medicine