Lazy Eye – Amblyopia – Strabismus

Lazy Eye – Amblyopia – Strabismus

Lazy Eye – Amblyopia – Strabismus

The Difference Between Lazy Eye (Amblyopia) and Strabismus

Many people make the mistake of saying that a person who has a crossed or turned eye (strabismus) has a “lazy eye,” but lazy eye (amblyopia) and strabismus are not the same condition. Some of the confusion may be due to the fact that strabismus can cause amblyopia. Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses. This almost always affects only one eye but may manifest with reduction of vision in both eyes.

If a patient has amblyopia, or `lazy eye.` This is an eye with limited visual potential because it was partially or totally ignored by the brain during the years of visual development. Usually this occurs because the eye was unable to image objects as clearly as the fellow eye. Treatment is only successful at young ages, and rarely beneficial after age 10. Correction of an underlying refractive error may be of some benefit. Children are generally referred to a pediatric ophthalmologist for evaluation and treatment.


Strabismus is a visual defect in which the eyes are misaligned and point in different directions. One eye may look straight ahead, while the other eye turns inward, outward, upward or downward.

You may always notice the misalignment, or it may come and go. With normal vision, both eyes aim at the same spot. The brain then fuses the two pictures into a single, three-dimensional image. This three-dimensional image  gives us depth perception.

What causes strabismus?

The exact cause of strabismus is not fully understood. Six eye muscles, controlling eye movement, are attached to the outside of each eye. In each eye, two muscles move the eye right or left. The other four muscles move it up and down and at an angle.

If surgery is required

The eyeball is never removed from the socket during any kind of eye surgery. The ophthalmologist makes a small incision in the tissue covering the eye to reach the eye muscles.

Certain muscles are repositioned during surgery, depending on which direction the eye is turning. It may be necessary to perform surgery on one or both eyes.

When strabismus surgery is performed on children, a general anesthetic is required. Local anesthesia is an option for adults. Recovery time is rapid. People are usually able to resume their normal activities within a few days.

After surgery, glasses or prisms may be useful. In many cases, further surgery may be needed at a later stage to keep the eyes straight.

For children with constant strabismus, early surgery offers the best chance for the eyes to work well together. In general, it is easier for children to undergo such surgery before school age.

As with any surgery, eye muscle surgery has certain risks. These include infection, bleeding excessive scarring and other rare complications that can lead to loss of vision.

Strabismus surgery is usually an effective treatment for eye misalignment. It is not, however, a substitute for glasses or amblyopia therapy.

Watch Dr. Jason Cheung performing Strabismus surgery.


More to explore:

What to Expect at Your Child’s First Exam

Adult Strabismus 

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