What Is Strabismus?

Strabismus is a condition in which the eyes do not properly align with each other when looking at an object.This is one of the most common eye disorders in children, affecting about 4% of children (girls or boys) before 6 years of age . In this eye disorder, one or both eyes may deviate inward, outward, upward, or downward. It is more likely to exist more than one of these eye movement disorders at the same time in a child. The other name of this disease is "Squint" or " crossed eyes". Tehran-Iran Noor Eye Hospital has a super speciality strabismus clinic.

Eye Teaming

When vision is normal (binocular vision), the two eyes focus on the same spot and the brain combines the images of the both eyes into a single, three-dimensional image which results in depth perception. When one of the eyes is not in its normal visual axis, two different images are sent to the brain. In children with strabismus, the brain will learn to ignore the image of the misaligned eye and only see the image of the healthy straight eye; however, even if there is a double vision at first, it quickly disappears and the child loses depth perception.

Adults with acquired strabismus are often have double vision because their brains receive two images from both eyes and can not ignore the image of the misaligned eye.


Six extraocular muscles are involved in controlling the movements of the eyes, one of these muscles moving the eye to the inside and the other to the outside. Four other muscles are responsible for the movement of the eye upward, downward, and side to side. Focusing both eyes on the same spot require coordinated action of extraocular muscles. Simultaneous movements of both eyes requires coordinated action of extraocular muscles too. The brain controls extraocular muscles function, and impaired function of each extraocular muscle or brain leads to strabismus.

Other eye diseases that reduce vision, such as cataracts or eye injury, may also lead to strabismus. In many children with strabismus , the exact cause of the disease is unclear.

Note: Strabismus is more common in children with a familial history of this disease.


1. Deviation of one or both of the eyes to the inside, outside, up or down (the most important sign)

2. Failure to focus two eyes on an object continuously.

3. Squint one eye in bright light.

4. Tilting head to one side


Most Common Types of Strabismus

Congenital Esotropia: In this case, the most common type of strabismus in the pediatric population,in which the eye turns inwards. In most cases, the treatment of this type of strabismus is surgery.

Accomodative Esotropia (Refractive Esotropia) : It is one of the common types of strabismus over the age of two years. In this case, one of the eyes is diverted to give a clearer view of the objects at distances, near or both. This disorder can be treated with eye glasses and sometimes bifocal glasses, but if it can not be corrected with glasses, surgery will be recommended.

Exotropia: It is another common type of strabismus. In this case, the eyes are deviated outwards when the child is trying to focus on an object, especially in a distance. This disorder may occur intermittently, especially when the patient is tired or sick. Sometimes the only sign of a disease is squinting one eye in bright sunlight. Treatment for this problem in mild cases include the use of eye glasses, ophthalmic exercises, patching of the preferred eye or wearing prism eyeglasses, but in most cases, particularly in acute cases, the definitive treatment for this disorder is surgery.

 Pseudostrabismus (False Appearance of Strabismus)

A condition called pseudostrabismus (false strabismus) can make it appear that a baby has crossed eyes when in fact the eyes are aiming in the same direction. The eyes of a child with pseudostrabismus seem to be convergent or divergent, while they are in fact aligned. The first case is common in infants and young children, due to the broad flat nasal bridge or the presence of skin folds between the nose and the inner corner of the eyelids. This condition gradually normalizes with the children's growth and during their puberty.

In the latter case, that is less common, the eyes seem to turn outward, but in fact they are aligned and this appearance is due to the specific shape of the face. In order to detect the difference between  strabismus and pseudostrabismus, a comprehensive eye examination at Tehran-Iran Noor Eye Hospital is recommended.


Strabismus treatment for children is performed on the basis of the following criteria:

 1. The child's age, general health and medical history

2. The child's tolerance for specific treatments

3. The cause of strabismus

 4. Type of strabismus and its severity

Note: Treatment includes one or more of the following:

 -Eye glasses or prism glasses

- Eye drops

- Eye exercises

- Using the eye patching on one or both eyes alternately (if the patient suffers from lazy eye too,  this method helps to correct it too.)

- Surgery: If an ophthalmologist diagnoses that other treatments are not successful, surgery will be the safest and most effective treatment for strabismus. All kinds of treatments for strabismus are available in Tehran-Iran Noor Eye Hospital, under the supervision of expert ophthalmologists.

Strabismus Treatment Goals

 1. Improve eye alignment

2.  Restore eye teaming (visual efficiency skill that allows both eyes to work together)

3. Perfect vision development and achieve binocular vision


If the surgery is done under general anesthesia or under local anesthesia with sedation, the patient should be monitored after surgery. Children can return to school two days after surgery. Adults are not allowed to drive after surgery and the following day. They also need about one week off work after surgery. After surgery double vision may last for a few hours, days or weeks or more, of course, it lasts rarely longer than a week. During this period, the patient should be cautious when performing certain activities, especially driving.

Postoperative pain is minor and is usually slowed down by the use of painkillers such as Ibuprofen (Motrin) or Acetaminophen (Tylenol) and cold compress. The ophthalmologist prescribes for adults and older children painkillers. The main restriction after strabismus surgery is no swimming  for two weeks. The eyes will be red for one to two weeks after surgery, especially if it is a secondary or reconstructive surgery.


Ophthalmologists' Advice to Parents

 An early diagnosis and timely treatment of strabismus can prevent permanent irreversible damage to eyesight. Eye examination is recommended for all children. If your child has symptoms of strabismus or if you have a family history of strabismus, lazy eye or other eye diseases, your child needs to have a comprehensive eye examination as soon as possible and at the age of 3 years.

- What is strabismus?

- Does gender play an effective role in strabismus?

-What are the common symptoms of strabismus?

- What is the best age for strabismus treatment?

- Can strabismus be treated at older ages?

- Is it possible to treat strabismus with drug therapy?

 - What are the post-operative limitations?




- What is strabismus?

Strabismus is a condition in which the eyes do not properly align with each other. This is one of the most common eye disorders in children.

- Does gender play an effective role in strabismus?

 Well, gender does not play a role in strabismus; about 4% of all children under the age of 6 have strabismus.

-What are the common symptoms of strabismus?

1. Deviation of the child's eyes to the inside, outside, up or down (the most important sign)

2. Failure to focus two eyes on an object continuously.

3. Squint one eye in bright light.

4. Tilting head to one side.

- What is the best age for strabismus treatment?

Treatment between 2 to 6 years of age is ideal and allows better results than later treatment.

- Can strabismus be treated at older ages?

 Yes; of course, it should be noted that as you age, the treatment process will be more difficult.

 - Is it possible to treat strabismus with drug therapy?

 Strabismus treatment includes non-invasive (non-surgical) and invasive (surgical) methods. However, in most cases, surgery is the best treatment to achieve normal vision.

 - What are the post-operative limitations?

 1. Children should not go to school or play for two days.

 2. Adults should rest at home for one week and driving should be avoided for at least two days  after surgery.