Strabismus FAQs


What is strabismus?
How do the eyes work together?
Types of strabismus
What causes strabismus?
Will a child outgrow strabismus?
What can increase a child's risk of strabismus?
How is strabismus detected?
How is strabismus diagnosed?
How is strabismus treated?
How is strabismus surgery done?
What anesthetic is used in strabismus surgery?
Before and After


WHAT IS STRABISMUS?
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. The turned eye may straighten at times and the straight eye may turn.

Strabismus is a common condition among children. It can also occur later in life.

It occurs equally in males and females. Strabismus may run in families. How ever, many people with strabismus have no relatives with the problem.

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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.

When one eye turns, 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 misaligned eye then becomes "lazy".
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.

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 strengthen and improve vision in the weaker eye. If amblyopia is detected in the first few years of life, treatment is usually successful.

If treatment is delayed until later, amblyopia usually becomes permanent. As a rule, the earlier amblyopia is treated, the better the visual result.

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TYPES OF STRABISMUS?

With normal vision, both eyes aim at the same spot. The brain then puts the two pictures into a single, three-dimensional image. This blending or fusing of the two pictures gives us depth perception. There are several types of strabismus.

Esotropia is an eye misalignment where the eye turns inward towards the nose. It can affect one or both eyes and can alternate between the two eyes.

Exotropia is a misalignment in which the eye turns outward, away from the nose.

Hypertropia is an upward gaze or appearance of the eye while the other eye stays straight and fixates normally.
When one eye turns, two different pictures are sent to the brain. In a child, the brain learns to ignore the picture from the misaligned eye, and sees only the image from the straight one. This causes poor vision in the misaligned eye. It takes away the ability to have and develop depth perception.

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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 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.

The brain controls the eye muscles. Strabismus is especially common among children with disorders that affect the brain, such as:

  • Cerebral palsy

  • Down syndrome

  • Hydrocephalus

  • Brain tumors

  • A cataract or eye injury that affects vision can also cause strabismus.

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WILL A CHILD OUTGROW STRABISMUS?
A child rarely outgrows strabismus once it has developed. Without treatment, strabismus can cause permanent vision problems. For example, if the child is not using one eye because it is misaligned, he or she can develop poor vision in that eye (called lazy eye or amblyopia).

A newborn's eyes may initially be misaligned, but the eyes should become aligned by 3 to 4 months of age. In some cases, the eyes may simply seem to be misaligned because the child has a wide bridge of the nose that creates the appearance of crossed eyes (pseudostrabismus).

Any child older than 4 months whose eyes are not aligned all of the time should have an eye exam by an ophthalmologist. This exam should be done sooner if there is an obvious problem.

WHAT CAN INCREASE A CHILD'S RISK OF STRABISMUS?

Risk factors for childhood strabismus include:



HOW IS STRABISMUS DETECTED?
For children found to have strabismus, it is usually parents, family friends, or pediatrician who first notice that a child’s eyes do not appear straight. Occasionally, the red reflection often seen in the pupils of eyes in photographs may appear asymmetrical, which can be a sign of misalignment. Vision testing in school can also help to diagnosis children with strabismus. In families with a history of strabismus or "lazy eye," attention should be paid to signs of strabismus so treatment can be rendered as soon as possible.
Adults who develop strabismus almost always discover the condition themselves as they almost always develop the very bothersome symptom of double vision.

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HOW IS STRABISMUS DIAGNOSED?
Strabismus can be diagnosed during an eye exam. It is recommended that all children have their eye checked by their pediatrician, family doctor or ophthalmologist (medical eye doctor) at or before school age or if an eye misalignment can be seen. If there is a family history of strabismus or amblyopia, an ophthalmologist can check vision even earlier.

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HOW IS STRABISMUS TREATED?
Treatment for strabismus works to:

  • Preserve vision

  • Straighten the eyes

  • Restore binocular (two-eyed) vision

  • 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.

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HOW IS STRABISMUS SURGERY DONE?


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 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 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 under go 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 a safe and effective treatment for eye misalignment.
It is not, however, a substitute for glasses or amblyopia therapy.

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WHAT ANESTHETIC IS USED IN STRABISMUS SURGERY?
Usually strabismus surgery is performed under general anesthesia. Sometimes surgery can be performed while the individual is awake or slightly sedated. In this situation, an indictable local anesthetic or anesthetic eye drops are used.

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LARRAZABAL EYE PRE OP AND POST OP

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