What is strabismus?

Strabismus, or “eye turn”, is a condition in which a person’s eyes do not point to the same place at the same time. This results in one eye looking at an object while the other turns in, out, up, down. This eye misalignment may be constant or intermittent, and it can switch back and forth between eyes. This is often noticeable in social interactions and can impact an individual’s self esteem. It also causes problems with depth perception and can lead to amblyopia.

Types of strabismus and treatment

Strabismus always requires treatment. It rarely goes away by itself and children do not outgrow it. The specific treatment is dependent on the type and cause of eye turn. Treatment often consists of prescription lenses, prisms, patching and a program of vision therapy. In certain patients, surgery may be recommended in conjunction with vision therapy.

• About 77% of infants are born with eyes that are not pointed in the same direction. Within the first three months the eyes gradually start to work together as a team. No treatment is required.
• Infantile Esotropia appears around 2 to 4 months of age. It is a large inward eye turn and the baby often alternates which eye they are using. This type of strabismus mostly requires surgery. Other treatment options can include glasses, patching, tape applied to the inner third of each lens, prism glasses, and vision therapy.
• Accommodative Esotropia is often first seen around 2 or 3 years of age. With this condition, the eyes turn in too much when they look at near objects. The inward turning might only occur when they look up close only, in which case the patient could only need glasses for looking at near objects. In other cases the patient may be significantly far-sighted, which can cause the inward turn to occur when the child is looking at near and far. For these cases, bifocals may be prescribed. In addition to glasses, vision therapy or patching is often useful to teach the eyes how to work together. Surgery should never be done.
• Partially Accommodative Esotropia is when part of the inward turn is due to infantile esotropia and part is due to accommodative esotropia. Glasses may reduce the amount of eye turn, but there is often a small eye turn left. Prism, vision therapy, and surgery are additional treatment options.
• Exotropia is the term for when one eye is turned out toward the patient’s ear. There are many causes of exotropia. Depending on how far the eye drifts out and how often, treatment options include vision therapy, prism, and surgery.
• Acquired Strabismus is one that often due to systemic problems, tumors, or trauma. This type may go away on its own, or may require prism, vision therapy, or surgery.

Extra-ocular muscle surgery (a.k.a. strabismus surgery)

When surgery is recommended, it should be in conjunction with a vision therapy program. Vision therapy prior to surgery increases the possibility of a successful surgery. Without vision therapy, surgery may make the eyes look straight, but the brain still doesn’t know how to use them together, so depth perception is not obtained. If amblyopia is present, patching therapy should also be done before any surgery. The possibility of a successful outcome is reduced with each successive surgery. Success is still possible, even with multiple surgeries, but can be more difficult. There are no studies show that surgery is more successful at any particular age. A few studies show greater success if surgery is performed before one year of age, but other studies contradict this finding.