What is Strabismus?

Strabismus is defined as the inability of the eyes to focus on the same point or to work in coordination. In the case of strabismus, one eye may look at the desired target while the other eye may drift in any direction. Strabismus can occur in 5% of children. There are many factors that cause strabismus and there are many types of strabismus. Strabismus can occur from birth or at later ages. Some genetic factors can cause strabismus, but many strabismus patients do not have a genetic disorder or additional disease.

What are the Causes and Symptoms of Strabismus?

There are many types of strabismus. While the mechanism of some of these strabismus types is known, the exact cause of many of them is not known. There are six muscles that move each of our eyes. The coordination of eye movements is provided by the brain that controls these muscles. In order for both eyes to look at the same target, both brain structures and muscles must work in balance and coordination. Eye diseases such as vision-impairing cataracts or the need for high-prescription glasses, brain diseases, and muscle diseases can disrupt the working order between the brain and muscles and cause strabismus.

The most important symptom of strabismus is constant or occasional eye squints. Head turning or head tilting in various directions may be observed to keep the eyes in the midline. The symptom of strabismus that develops suddenly, especially in adults, is double vision.

How is Strabismus Diagnosed?

Since there are many types of strabismus, making the correct diagnosis is extremely important in determining treatment options. Strabismus is diagnosed with a complete eye examination. During the examination, the patient’s vision level and refraction errors are first determined; then, eye movements are evaluated. Presence of depth perception is evaluated. After applying eye drops that dilate the pupil, intraocular tissues and optic nerves are examined. After all examination steps are completed, the type of strabismus is determined and appropriate treatment options are presented to the patient.

Why Should Strabismus Be Treated?

The fact that people have two eyes and that the two eyes move in coordination is critical for 3D perception. When an object is focused on, an image is formed in each eye. These two images are combined in the brain to obtain a single, 3D image. We use the 3D vision function unconsciously in many activities in daily life, such as walking, climbing stairs, identifying objects, and estimating distances.

In a patient with strabismus, since the eyes focus on different objects, two different images that do not resemble each other are formed in the eyes, and the brain cannot combine these images to create a single 3D image. This leads to double vision. Especially in children under the age of 10, the brain begins to ignore the image coming from the deviated eye in order to protect itself from double vision. When this condition is not treated, the vision of the deviated eye decreases over time and this condition is called amblyopia (lazy eye). This condition only develops in children under the age of 10. Such a condition does not occur in the adult brain and double vision continues.

If strabismus, which causes amblyopia, is not treated in time, the amblyopia becomes permanent and cannot be treated after the age of 10. In order to avoid this situation, it is extremely important to start amblyopia treatment after strabismus is corrected with surgical or non-surgical methods in patients with strabismus. With the right diagnosis and treatment, amblyopia can be completely eliminated and 3-dimensional vision can be regained.

Since each patient’s needs and type of strabismus are different, strabismus treatment is planned specifically for each patient. While some patients cannot be resolved without surgery, surgical applications are specifically avoided in some patients. In some types of strabismus, both surgical and non-surgical methods are applied together.

Non-surgical treatment methods

• Use of glasses
• Use of prismatic glasses
• Eye closure treatment
• Vision rehabilitation

Surgical treatment

If there is a need for surgery in strabismus patients, it is very important to perform the surgery as early as possible. Because in babies or children, normal vision and depth perception can develop after the deviation of the eyes is corrected. As children grow, the possibility of developing normal vision and depth perception decreases. Although it is not possible for vision and depth perception to fully develop after the average age of 10, there may be an expansion in peripheral vision when strabismus is eliminated. Strabismus surgery is not an  alternative to using glasses and amblyopia treatment. The glasses used and the amblyopia treatment applied before the surgery are continued in the same way after the surgery.

What happens when strabismus is not treated?

When strabismus is not treated, the level of visual acuity in the deviated eye gradually decreases and an increase in the angle of deviation may be observed in patients below age of 10. Although treatment is possible up to the age of 10, the success of treatment methods decreases as the patient gets older. After the average age of 10, it is not possible to treat amblyopia. Since 3D vision is impaired and the level of vision is low in patients with strabismus, children may experience delayed walking, walking disorders, difficulty in learning and a decrease in social skills.

What is the Pre-Surgery Process?

After the examination, all patient data are evaluated and a treatment option is presented to the patient. The patient is informed about the gains of the surgery, the negative situations that may occur if surgery is not performed and the possible risks of surgery. The patient’s possible problems and questions are evaluated and answered in detail. After the patient’s decision for surgery, the patient is evaluated by the anesthesiologist and surgery is planned after the approval of general anesthesia.

How is Strabismus Surgery Performed?

If there is no contraindication, strabismus surgery is performed under general anesthesia. In strabismus surgery, the eye muscles are weakened, strengthened or the places of the eye muscles can be changed according to the patient’s needs. Basically, surgical procedures are performed on the muscles located on the outer part of the eyeball. All critical structures that enable us to see are located inside the eyeball, and in strabismus surgery, there is no intervention in the intraocular structures that enable vision. These structures remain outside the scope of strabismus surgery. The stitches used during surgical procedures are self-dissolving and do not require removal after surgery.

What is the post-operative process?

Although the healing response of each person and each eye varies, the healing process in strabismus surgeries is quite fast. Redness may be observed around the eyes in the first days after surgery. This redness disappears quickly within 1 week. Patients can return to their normal lives within 1-2 days. It is recommended to avoid contact with water and manual intervention in the eye for 3 days after surgery. There are no restrictions, including swimming in the pool or the sea, 10 days after surgery.

There are control examinations on the 1st day, 1st week and 1st month after the surgery. Patients may need to use glasses or prism lenses after the surgery. After the surgery, the brain is expected to combine the images from the new eye position and keep the eyes in the midline. When the brain cannot achieve this combination, secondary shifts may occur over time (months or years) and surgery may be considered again.