SQUINTING - STRABISMUS

• What Is The Strabısmus?
• What Causes Strabismus?
• What Are The Symptoms?
• How İs Strabismus Diagnosed?
• The Most Common Types Of Strabismus
• What Is The Treatment?
• How İs Strabismus Surgery Done?

WHAT IS THE STRABISMUS?
Strabismus, commonly known as squint, 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 may turn inward, outward, upward and downward.

         You may find that the misalignment is a constant feature, or it may come and go. The turned eye may straighten at times and the straight eye may turn.

Strabismus is common among children. About 4% of all children in the United States have strabismus. It can also occur later in life.

         In occurs equally in males and females. Strabismus may run in families. However, many people with strabismus have no relatives with the problem.This misalignment often first appears before age 21 months but may develop as late as age 6. This is one reason why we recommend a comprehensive optometric examination before 6months and again at age 3.
There is a common misconception that a child will outgrow strabismus. This is not true. In fact, the condition may get worse without treatment.

WHAT CAUSES STRABISMUS?

The exact cause of strabismus is not fully understood. Six eye muscles, controlling the 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 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 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, and
• Brain tumors.

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

WHAT ARE THE SYMPTOMS?
The main symptom is an eye that is not straight. Sometimes children will squint with 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 examination. It is recommended that all children have their vision checked by their pediatrician, family doctor or ophthalmologist on or before their fourth birthday. If there is a family history of strabismus or amblyopia, an ophthalmologist can check the vision even before the age of three.

An infant's eyes may seem to be crossed. 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 appearance of strabismus may reduce as the child grows. A child will not outgrow true strabismus.

An ophthalmologist can usually tell the difference between true and false strabismus

THE MOST COMMON TYPES OF STRABISMUS

• Esotropia
• Exotropia

Esotropia
Esotropia, where the eye turns inward, is the most common type of strabismus found in infants. Young children with esotropia do not use their eyes together. In most cases early surgery can align the eyes.

During surgery, the tension of the eye muscles in one or both the eyes is adjusted. The tight inner muscles may be removed from the wall of the eye and placed further back on the eye. This adjustment weakens the pull and allows the eyes to move outward. Sometimes the outer muscles are tightened by shortening the muscle length, to allow the eyes to move outward.

Accommodative esotropia
Accommodative esotropia is a common form of esotropia that occurs in farsighted children two years of age or older. When a child is young, he/she can focus the eyes to adjust for the farsightedness, but the focusing effort (accommodation) needed to see clearly causes the eyes to cross.

Glasses reduce this focusing effort and can help straighten the eyes. Sometimes bifocals are needed for close work. Eye drops, ointments, or special lenses called prisms can also be used to straighten the eyes.
Exotropia
Exotropia or an outward-turning eye is another common type of strabismus. This occurs most often when a child is focusing on distant objects. The exotropia may occur only from time to time, particularly when a child is daydreaming, ill or tired. Parents often notice that the child squints one eye in bright sunlight.

Although glasses, exercises or prisms may reduce or help control the outward-turning eye in some children, surgery is often needed.
TREATMENT?
The treatment goal for strabismus is to preserve vision, to straighten the eyes, and to restore 3-dimensional vision. If amblyopia is detected in the first few years of life, treatment is often successful. If treatment is delayed until later, amblyopia or reduced vision generally becomes permanent. Occlusive patching of the better seeing eye can force use of the amblyopic eye and improve vision. Depending on the cause of the strabismus, treatment may involve repositioning the unbalanced eye muscles, removing a cataract, or correcting other conditions that are causing the eyes to turn. After a complete eye examination, including a detailed study of the inner parts of the eye, an ophthalmologist can recommend appropriate optical, medical or surgical treatment.

Treatment for strabismus may include single vision or bifocal eyeglasses, prisms, vision therapy, and in some cases, surgery. Vision therapy helps align your eyes and solves the underlying cause of strabismus by teaching your two eyes to work together. Surgery alone may straighten your eyes, but unless your eye muscle control is improved, your eyes may not remain straight.If detected and treated early, strabismus can often be corrected with excellent results.

Early surgery is often recommended to correct strabismus in younger infants, who can then develop normal acuity and binocular (stereo) vision once the eyes are straightened. As a child gets older, the chance of developing normal sight and depth perception decreases. Crossed eyes can also have a negative effect on a child's social interaction and self-confidence.
HOW IS STRABISMUS SURGERY DONE?
Strabismus surgery involves making a small incision in the tissue covering the eye, which allows the ophthalmologist to access the underlying eye muscles. The eyeball is never removed from the socket during this kind of eye surgery. Which eye muscles are repositioned during the surgery depends upon the type of strabismus. It may be necessary to perform eye muscle surgery on one or both eyes. When strabismus surgery is performed on children, a general anesthetic is required; a local anesthetic is often an option for adults.
Eye muscle surgery is generally performed as an outpatient procedure in a hospital or a surgery center. Recovery time is rapid and the patient is usually able to resume normal activities within a few days. Following surgery, glasses or prisms may sometimes be needed. Over-or-under correction can occur and further "touch-up" surgery may be needed. As with any surgery, eye muscle surgery has certain risks which include infection, bleeding, excessive scarring, and other complications that very rarely may lead to loss of vision.