Strabismus and Eye Misalignment Surgery

Strabismus also known as squint, occurs when an eye turns involuntarily. Strabismus, is a condition in which the eyes are incorrectly aligned and look at different points. One eye may look straight ahead while the other turns outward, upward, inward or downward. Misalignment may be constantly visible or appear only when looking in certain directions. To correct it, extraocular muscle strabismus surgery is performed.

In strabismus, either eye may turn horizontally, vertically or torsionally. It can affect children or adults.

The condition is categorised as congenital, acquired, restrictive or paralytic. Strabismus surgery aims to return the eyes to their normal anatomical positions and maximise the potential for both eyes to work together (binocular vision). Other goals include eliminating double vision, in which a single object appears as two adjacent images horizontally, vertically or obliquely; relieving mechanical restriction; and restoring a normal head position. Surgery can improve vision in cases of nystagmus.

One or more muscles on the outside of the eyeball may be operated on. Procedures on both eyes are common. Adjustable-suture surgery is used in some cases.

Operations are performed under general anaesthesia with the patient asleep, although local anaesthesia may be preferred in some cases. Local anaesthesia can be used for standard muscle-weakening procedures in patients who are good candidates for conscious sedation.

Strabismuscan be categorised according to the direction of the turned or misaligned eye:

• Inward turn (esotropia)
• Outward turn (exotropia)
• Upward turn (hypertropia)
• Downward turn (hypotropia)

Other factors that help determine the cause and treatment of strabismus:

Did the problem arise suddenly or gradually?

• Was it present in the first 6 months of life or did it appear later?
• Does it always affect the same eye or alternate between the eyes?
• Is the degree of turning small, moderate or large?
• Is it always present or only some of the time?
• Is there a family history of strabismus?

What causes strabismus?

Most strabismus results from abnormal neuromuscular control of eye movement. Although the brain centres controlling these muscles are not fully understood, research continues to provide new information. Less commonly, there is a problem with the eye muscle itself. Strabismus is often inherited, and approximately 30% of children with strabismus have a family member with a similar problem.

Strabismus is also associated with:

• Uncorrected refractive errors.
• Poor vision in one eye (amblyopia).
• Cerebral palsy (brain damage).
• Down syndrome (20–60% of these patients are affected).
• Hydrocephalus, a congenital condition causing fluid build-up in the brain.
• Brain tumours.
• Stroke, a leading cause of strabismus in adults.
• Head injuries that may damage the brain region responsible for eye movement, the nerves controlling eye movement or the eye muscles.
• Neurological (nervous system) problems.
• Graves’ disease (overproduction of thyroid hormone).

How is strabismus diagnosed?

Every child over four months old who appears to have strabismus should have a complete examination by a paediatric ophthalmologist, including an assessment of how the eyes focus and move.

The following assessments are needed:

• The patient’s medical history.
• The patient’s symptoms.
• Family history.
• General health problems, medicines used and other possible causes of symptoms.
• Visual acuity, assessed by reading letters on an eye chart or examining visual behaviour in young children.
• Refraction, assessed using corrective lenses to measure how the eyes focus light.
• Children do not need to be old enough to give verbal feedback when their glasses prescription is checked.
• Alignment and focusing tests.
• Examination of the internal eye structures to assess their health.

How is it treated? Treatment options include:

• Glasses or contact lenses: Used for patients with uncorrected refractive errors. Corrective lenses reduce the effort needed to focus and help the eyes remain straight.
• Prism lenses: Special lenses bend light entering the eye and help reduce how far the eye needs to turn to view objects.
• Orthoptics (eye exercises): May help certain types of strabismus, particularly convergence insufficiency, a form of exotropia.
• Medicines: Eye drops or ointments may be used. Botulinum toxin type A injections can also weaken an overactive eye muscle. Depending on the patient’s condition, these treatments may accompany or replace surgery.
• Eye patching: When amblyopia occurs alongside strabismus, patching may improve vision and control of eye misalignment.
• Eye muscle surgery: In strabismus surgery, the length or position of the eye muscles is changed to align the eyes correctly. This is performed under general anaesthesia using dissolving stitches. Adults may sometimes undergo a procedure that allows the eye muscle positions to be adjusted after surgery: strabismus surgery is performed.

What can happen if it is not treated?

Unfortunately, it is commonly believed that children will outgrow strabismus or recover spontaneously. This is not true, and untreated childhood strabismus may worsen over time.

If strabismus is not corrected and the eyes remain misaligned, the following complications may occur:

Lazy eye (amblyopia) or permanent visual impairment in the turned eye. When the eyes look in different directions, the brain receives two images. To avoid double vision, it may ignore the image from the turned eye, causing poor vision to develop in that eye.

• Blurred vision that may affect performance at school and work and reduce enjoyment of hobbies and leisure activities.
• Eye strain.
• Fatigue.
• Headache.
• Double vision.
• Poor three-dimensional vision.
• Embarrassment about appearance.
• Failure to diagnose strabismus may also mean missing a serious underlying problem, such as a brain tumour causing the condition.

What can be expected after strabismus treatment?

Regular visits to the eye surgeon are essential to assess the response to treatment and make further adjustments if necessary.

In children, strabismus can be detected early and then treated appropriately. This may result in excellent vision and depth perception and help protect against vision loss.

If you or your child has strabismus, contact us now.  strabismus surgery Please book an appointment with our eye surgeon who specialises in this condition.

Dr. Hüseyin CENGİZ

Dr. Efsane H. CENGİZ

Dr. Ümit ATİK

Dr. Ali ÖZER

Dr. İdil GÖKSEL

Dr. Fatih BALTU

Dr. Ümit YAPICI

Click the useful links below: Our Oculoplastic Eye Surgeon, What is strabismus? (External source)