PATIENT LIBRARY


STRABISMUS:

What is Strabismus?

Strabismus is a visual defect in which the eyes are misaligned and is a common condition among children. 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. It may also appear to alternate between eyes. Strabismus may run in families, but many people with strabismus have no relatives with the problem. It occurs equally in males and females, and may appear for the first time soon after birth or later in life as an adult.

How do the eyes work together?

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. IN the presence of strabismus, two different pictures are sent to the brain. In a young child, the brain learns to ignore the image of the misaligned eye and sees only the image from the straight or better-seeing eye. The child then looses depth perception. Adults who develop strabismus often have double vision because the brain is already trained to receive images from both eyes and cannot ignore the image from the turned eye.

What causes Strabismus?

The exact cause of strabismus is not fully understood. Six eye muscles, controlling eye movement, are attached to the outside of the eye. In each eye, two muscles move the eye right or left. The other four muscles move it up or down and at an angle. To line up and focus both eyes on a single target, all of the muscles in each eye must be balanced and working together. In order for the eyes to move together, the muscles in both eyes must be coordinated.

What are the symptoms of Strabismus?

The main sign of strabismus is an eye that is not straight. Sometimes children will squint one eye in bright sunlight or tilt their head to use their eyes together.

How is Strabismus diagnosed?

Strabismus can be diagnosed during an eye exam. It is recommended that all children have their vision checked by their pediatrician, family doctor or ophthalmologist, at or before their fourth birthday. If there is family history of strabismus, or amblyopia, an ophthalmologist can check vision even earlier. Young children often have a wide, flat nose, and a fold of skin at the inner eyelid that can make the eyes appear crossed. This pseudostabismus may improve as the child grows. A child will not outgrow true strabismus. An ophthalmologist can tell the difference between true and false strabismus.

Can Strabismus cause a reduction in vision known as Amblyopia?

Good vision develops during childhood when both eyes have normal alignment. Strabismus may cause reduced vision, or amblyopia, in the weaker eye. The brain will recognize the image of the better-seeing eye and ignore the image of the weaker or amblyopic eye. This occurs in approximately half the children who have strabismus. Amblyopia can be treated by patching the "good" eye to straighten and improve the vision in the weaker eye. If amblyopia is detected in the first few years of life, treatment is usually successful. Patching the eye to treat amblyopia is most successful when the child is pre-school age. If treatment is delayed until later, amblyopia usually becomes permanent. As a rule, the earlier amblyopia is treated, the better the visual result.

How is Strabismus treated?

Treatment for strabismus works to:

After a complete eye examination, an ophthalmologist can recommend appropriate treatment. In some cases, eyeglasses can be prescribed for your child. Other treatments may involve surgery to correct the unbalanced eye muscles or to remove a cataract. Covering or patching the strong eye to improve amblyopia is often necessary.

Most common types of Strabismus:

How is Strabismus surgery done?

The eyeball is never removed from the socket during any kind of surgery. The ophthalmologist makes a small incision in the tissues covering the eye to reach the eye muscles. Certain muscles are repositioned during the 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 prism may be useful. In some 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 surgery before school age. As with any surgery, eye muscle surgery has certain risks. These include infection, bleeding, excessive scarring and rare complications that can lead to loss of vision. Strabismus surgery is usually a safe and effective treatment for eye misalignment, but glasses or amblyopia therapy often are needed as well.

Botox™, a new drug approved by the U.S. Food and Drug Administration for limited use, is an alternative to eye muscle surgery for some individuals. An injection of this drug into an eye muscle temporarily relaxes the muscle, allowing the opposite muscle to tighten and straighten the eye. Although the effects of the drug wear off after several weeks, in some cases, the misalignment may be permanently corrected.