Strabismus Surgery in Turkey

Strabismus surgery is a microsurgical procedure aimed at restoring the eyes to a parallel position by making millimetric changes to the lengths or attachment points of the muscles that control the movements of the eyeball. This surgical intervention, performed as part of strabismus treatment, focuses on correcting the imbalance in mechanical pulling forces between the muscles. With strabismus surgery, the motor strength of weak muscles is supported while the tension of overactive muscles is reduced, thereby restoring anatomical alignment. This operation, which aims to physically repair the simultaneous movement ability of the eyes, is a functional treatment option that helps establish both aesthetic symmetry and healthy visual dynamics at the same time.

What are strabismus and strabismus surgery, and how do they affect visual quality?

In a healthy individual, there are six muscles controlling each eyeball. These muscles work in perfect balance and coordination, much like the ropes of a sailboat, allowing the eyes to move smoothly in every direction. When one eye wants to look in any direction, the corresponding muscles in the other eye contract or relax at the same rate through signals sent by the brain. However, when this delicate harmony is disrupted, the parallel alignment of the eyes is lost. While one eye looks toward the intended target, the other turns inward, outward, upward, or downward.

This physical difference is not merely a cosmetic condition; the main complexity occurs in the visual center of the brain. When both eyes focus on different points, two completely different images are transmitted to the brain. The brain has difficulty combining these two different images into a single meaningful visual image. This condition usually leads to visual confusion and the extremely tiring problem of double vision. When strabismus develops later in adulthood, the brain cannot tolerate this condition and the patient reports constant double vision. However, in infants and early childhood, the brain has a very high capacity for adaptation. In order to escape this double-vision confusion, the developing child’s brain suppresses the visual signals coming from the deviating eye and, in a sense, begins to ignore that eye.

The continuous rejection of signals coming from the deviating eye can cause the visual ability of that eye to weaken over time and create the basis for the condition commonly known as lazy eye. If not treated early, this visual loss may become permanent at later ages. In addition, the inability to use both eyes together eliminates our ability to perceive the world in three dimensions and with depth. A child with poor depth perception may stumble while going up or down stairs, have difficulty judging the distance of objects, and struggle with daily activities that require hand-eye coordination. For these reasons, strabismus surgery is a functional intervention aimed not only at improving appearance but also at enhancing visual performance in every aspect of life.

What are the types of strabismus, and in which situations is the decision for strabismus surgery made?

Strabismus problems are examined across a very broad spectrum according to the underlying cause, the direction of deviation, and the eye’s movement ability. Cases in which the amount of deviation remains the same in every direction of gaze are evaluated differently from those in which it changes according to gaze direction.

Common types of strabismus include:

• Inward deviations
• Outward deviations
• Latent deviations
• Paralytic deviations
• Deviations due to mechanical restriction

In inward deviations detected during infancy, generally within the first six months, and presenting with a high angle of deviation, the use of glasses alone may not be sufficient. In these infants, it is very important to plan surgical intervention at an early stage so that the brain’s habit of using both eyes together is not permanently damaged and the potential for three-dimensional vision is supported. On the other hand, the situation progresses somewhat differently in accommodative inward deviations, which generally develop due to refractive errors in the eye. Sometimes, when glasses with the appropriate prescription are worn, the deviation may improve to a large extent. However, if a significant deviation remains despite the glasses, surgery may be considered for this residual component.

Outward deviations generally begin to manifest during childhood when the child is distracted, tired, or feels the need to close one eye when going out into sunlight. Over time, the brain’s ability to control this deviation may become fatigued, the duration for which the eye remains outward may increase, and complaints such as eye pain and rapid fatigue may become more pronounced. Prolongation of the outward deviation and the patient beginning to lose control over it are among the most important factors in deciding on surgery.

In the group of strabismus cases in which the angle changes according to gaze direction, trauma, neurological conditions, or thyroid diseases are generally involved. When paralysis occurs in the nerves that originate from the brain and control the eye muscles, the relevant muscle cannot perform its function, and the patient experiences double vision when trying to look in that direction. In thyroid diseases, the structure of the eye muscles may change; the muscles may swell, lose elasticity, and become stiff. This restricts eye movements and leads to mechanical strabismus. In such systemic conditions, the underlying disease is first treated and allowed to stabilize; once the measurements remain stable for a certain period, planning for strabismus surgery begins.

What is evaluated during detailed eye examinations before strabismus surgery?

Achieving the desired result in strabismus surgery depends entirely on detailed preoperative examinations, multi-stage evaluations, and correct surgical planning. Before intervention, the anatomical and neurological condition of the eye must be analyzed very carefully.

The main tests and evaluations performed are:

• Dilated eye examination
• Prism cover tests
• Three-dimensional vision tests
• Eye motility examinations
• Forced duction test

In the first stage, a detailed refractive error examination is performed using special drops in order to rule out hidden prescriptions and accommodative spasm in the patient’s eyes. These drops temporarily relax the focusing muscles inside the eye. In this way, all hidden refractive errors that the patient has been trying to tolerate by straining the eyes are revealed, and the actual need for glasses is clearly determined. If the patient has lazy eye accompanying the strabismus, patching therapy is generally applied before surgery, in which the healthy eye is covered so that the weaker eye is forced to work. The better the lazy eye is managed, the greater the likelihood that the brain will keep the eyes in a straight position after surgery.

The amount of deviation is measured using special lenses called prisms. The degree of deviation is calculated numerically while the patient looks both near and far and in different gaze positions. Mechanical measurements alone are not sufficient; sensory tests are also used to understand how the brain uses the two eyes. With the help of special glasses and images, it is determined whether the patient sees double or completely suppresses and ignores one eye. In addition, the patient’s level of depth perception is examined. To understand whether there is paralysis in the eye muscles or a mechanical restriction, methods in which we manually test the eye’s movement ability on the operating table are sometimes also used. All of this information is brought together to create the most suitable surgical plan for the patient’s condition.

How do muscle weakening methods used during strabismus surgery work?

The main goal in strabismus surgery is to restore the disturbed balance by making millimetric changes to the anatomical attachment points or pulling forces of the muscles that move the eyeball. In this context, the pulling force of a muscle can be reduced, increased, or redirected.

In weakening procedures, the recession method is frequently preferred. This technique is used when a muscle pulls the eye strongly in an unwanted direction and works more than necessary. We can think of this muscle as a very tight elastic band. To reduce this excessive pulling force, the muscle is gently separated with surgical instruments from its natural attachment point on the white layer of the eye. According to preoperative millimetric calculations, it is then reattached to a new point farther back on the eye using fine, self-dissolving sutures.

When the attachment point of the muscle is moved farther back, the physiological length of the muscle becomes relatively longer and the area over which it wraps around the eyeball becomes smaller. This structural change helps weaken the mechanical pulling force of the muscle by a certain amount. However, the degree of recession must be adjusted very carefully. If the muscle is recessed too much, the patient may not be able to move the eye sufficiently when trying to look in that direction, and movement limitation may develop.

How are weak muscles strengthened as part of strabismus surgery?

In strengthening procedures, the aim is to increase the effectiveness of a muscle that has remained underactive, become weak, or cannot produce sufficient pulling force. For this purpose, a shortening technique generally known as resection is used.

A weak muscle resembles a structure that has stretched over time and lost its tension. To increase the pulling strength of the muscle, a small segment of a predetermined amount is removed from a region close to where the tendon attaches to the eye. Then the remaining portion of the muscle is pulled slightly forward and sutured back to its original attachment site.

As a result of this procedure, the physical length of the muscle becomes shorter and the resting tension in the muscle fibers increases. Because the shortened muscle becomes tighter, its motor pulling strength increases and it begins to pull the eye more strongly in its own direction. Weakening and strengthening procedures can generally be combined according to the patient’s angle of deviation so that they complement each other.

What is muscle folding (plication), one of the strabismus surgery techniques, and what does it do?

Although the shortening method is quite effective in muscle strengthening procedures, modern surgical approaches also include an alternative technique that allows less intervention in the tissue. This approach, known as the folding technique, offers important advantages in certain patient groups.

Some advantages provided by the plication procedure are:

• Preservation of muscle integrity
• Continuation of blood circulation
• Preservation of ocular blood supply
• Support of the healing process

In the folding method, the muscle tissue intended to be strengthened is not cut and removed. Instead, the end portion of the muscle is folded over itself by the predetermined amount, just like folding fabric, and is sutured to the eye wall in this position. The greatest benefit of this procedure is that it helps preserve the vital blood vessels supplying the front part of the eye. These vessels pass through the eye muscles to reach the eye; therefore, since the muscle is not cut, the vessels are not damaged either. This technique is often preferred especially in patients who have previously undergone multiple eye surgeries, in older patients with circulation problems, or in situations where many muscles need to be operated on in a single session, in order to greatly reduce the risk of impaired blood supply to the eye.

Who are combined procedures and muscle transposition surgeries performed during strabismus surgery suitable for?

In some special situations, instead of distributing the burden of strabismus surgery between both eyes, it may be more appropriate to perform both weakening and strengthening procedures on a single eye at the same time. For example, if one of the patient’s eyes is completely healthy but the other has very severe lazy eye or reduced vision, the intervention is usually concentrated on the deviating eye with poorer vision. The healthy eye is preserved, while the excessively pulling muscle in the deviating eye is weakened and the weak muscle is strengthened. The alignment success achieved by procedures distributed between both eyes and those performed on a single eye is generally quite similar.

In cases where paralysis of the eye muscles has occurred and there is no remaining potential for nerve recovery, classical muscle-shortening procedures may not produce the expected effect. This is because the paralyzed muscle has largely lost its ability to contract. In such situations, muscle transposition surgeries may be planned. The basic principle of this method is to make use of the strength of the other muscles surrounding the nonfunctioning muscle that are still working normally. A portion of the tendons of the functioning muscles is taken, shifted toward the direction of the paralyzed muscle, and sutured in place. In this way, the pulling force of the functioning muscles is transferred to the paralyzed region. By changing the direction of the biomechanical balance, the aim is to allow the patient to look straight ahead at least in the primary position and to reduce the complaint of double vision.

What is the adjustable suture technique used in strabismus surgery and how is it applied?

Another method developed to manage the patient’s individual tissue response in strabismus surgery is the adjustable suture technique. Normally, during surgery the muscle is fixed to the eye wall with permanent knots. However, in people who have previously undergone unsuccessful strabismus surgery, in thyroid patients, or in those with mechanical restriction, it may be difficult to predict in advance how the tissues will respond to surgery.

In such more specialized cases, the muscle is not tied permanently to the eye wall; instead, it is attached using a sliding loop mechanism. Within the first twenty-four hours after the operation is completed and the patient has awakened, the patient is examined while fully awake. The eye’s angle of deviation is measured again in real time. If the calculated dosage proves to be slightly too much or too little for the patient’s eye structure, after numbing the eye with drops, the physician can move the sliding knot a few millimeters forward or backward to loosen or tighten the suture. The knot is permanently locked at the point where the patient no longer sees double and the best eye parallelism is achieved. Since the patient needs to remain awake and calm during the procedure, this method is generally preferred in adult patients.

Can treatments such as Botox be used before or after strabismus surgery?

Although surgical intervention is the first treatment that comes to mind when strabismus treatment is mentioned, there are also medical supportive methods that we use during the preparation stage before surgery or afterward. One of the main options is botulinum toxin, commonly known as Botox. Botox works by creating temporary relaxation in the muscle into which it is injected.

Supportive treatments used during the process include:

• Botox injections
• Prism lenses
• Eye patching practices
• Vision exercises

In ophthalmology practice, Botox can be particularly useful in recently developed nerve palsies. For example, in a patient with nerve palsy, when the muscle that pulls the eye outward does not function, the healthy muscle that pulls the eye inward encounters no resistance. Because this healthy muscle contracts continuously, it may become stiff over time, almost as if it is cramping. In order to prevent this permanent stiffness, Botox may be injected with a millimetric needle into the healthy muscle that pulls too strongly during the first months of the condition. The muscle is temporarily relaxed for several months, and during this period time is gained for the other paralyzed muscle to recover.

In addition, in patients who have a very slight residual deviation after surgery or temporary double vision, prism glasses may be used to help combine the image into a single center. Special eye exercises aimed at increasing the coordination strength of the eye muscles are also frequently included in treatment planning.

How does the strabismus surgery process proceed, and what are the anesthesia methods and materials like?

Today, strabismus surgeries are generally performed as day-case surgical procedures. The patient comes to the hospital on the same day, undergoes the operation, and can usually be discharged later that same day after the necessary observation period. The choice of anesthesia varies according to the patient’s age, health condition, and the technique to be applied.

The anesthesia methods used are:

• General anesthesia
• Regional anesthesia
• Topical drop anesthesia

In children and infants, general anesthesia is preferred in order to ensure immobility during surgery and to prevent the patient from being psychologically affected in a negative way. In adults, depending on the situation, the procedure may be completed using regional anesthesia with injections around the eye or only with strong drops that numb the eye.

During the operation, a very small incision is made in the transparent outer membrane of the eye to reach the eye muscle. The location of the incision is determined according to the difficulty of the case and whether the patient has undergone previous surgery. Incisions made in areas hidden beneath the eyelid and not visible externally generally provide a more comfortable healing process aesthetically. As surgical material, synthetic sutures that are highly compatible with human tissue and dissolve on their own are used today. These sutures are generally completely absorbed by the body and disappear within a few weeks after surgery; therefore, no additional procedure such as suture removal is required afterward.

What is the recovery period like after strabismus surgery, and what are the possible risks?

After strabismus surgery, it takes a certain amount of time for the tissues to heal, for the eyes to adapt to their new alignment, and for the brain to accept this new condition. Patients are generally called for regular follow-up visits the day after surgery, during the first week, and in the following months. Mild sensitivity in the eye during the first few days is expected and can usually be managed comfortably with the prescribed drops.

Some possible conditions include:

• Temporary double vision
• Eye redness
• Mild stinging sensation
• Some residual deviation
• Inflammatory reactions

In the early postoperative period, some patients may experience temporary double vision. This is completely natural because the brain, which may have become accustomed to a deviated eye position for years, can have difficulty adapting for a short period when the eye is suddenly corrected. As the brain becomes accustomed to the new straight position of the eye within a few days or weeks, this double vision usually resolves on its own.

Sometimes, even when millimetric calculations are made, a mild deviation may remain due to the healing potential of the tissues, or the eye may turn slightly in a different direction than expected. Such situations may be monitored with prism glasses or, rarely, may require a small additional intervention several months later. Small tissue elevations related to the sutures or mild irritation on the corneal surface can be easily managed with topical drops. When surgical rules and the limits of intervention on the muscles are meticulously followed, rare serious risks such as impaired blood supply to the eye can also largely be prevented.

Why should evaluation for strabismus surgery be performed without delay?

Strabismus operations are not merely mechanical alignment procedures; they are comprehensive rehabilitation steps involving the patient’s brain, eye muscles, and nervous system. Careful monitoring of lazy eye, precise preoperative measurements, and meticulous application of the correct techniques during surgery are of great importance for the patient’s long-term visual health.

It is especially valuable for people who show signs of strabismus during childhood to be evaluated by a specialist ophthalmologist before the neurological development and learning window in the brain closes. Timely steps taken to prevent visual loss, support three-dimensional vision ability, and preserve a healthy eye structure throughout life make a permanent and positive contribution to the patient’s quality of life. In both children and adults, achieving healthy visual alignment is often possible through detailed analysis of the condition and correct treatment planning tailored to the individual.