Infantile Exotropia: Symptoms, Causes, and Treatment

Introduction:

Infantile exotropia is a condition in which one or both of a child's eyes turn outward. It is rare and starts before six months of age and stays beyond this age. It is called primary infantile exotropia if the baby is healthy and there are no signs of systemic or eye disease. Strabismus affects roughly four percent of the population. Exotropia is a common strabismus symptom. Although it can affect people of any age, it is typically diagnosed in childhood. Exotropia accounts for up to 25 percent of all eye alignment problems in children.

How Common Is Exotropia?

As it rarely happens, there are few population-based studies that can tell how often it happens. Archer et al. did a study and found that only two out of 3000 (or six out of 100 000) newborns have true primary infantile exotropia. Other researchers put this number at one out of 30,000 births in the general population. Older research suggested that people of Asian and African descent may be more likely to have infantile exotropia.

What Are the Causes of Infantile Exotropia?

• Genetics: Some families have members with strabismus or misaligned eyes, which can pass on to the next generations.

• Extremely Poor Eyesight: Exotropia can be brought on by low vision in one of the eyes.

• Neurological Disorders: Exotropia can be brought on by medical problems like tumors or stroke.

• Convergence Problem: Insufficiency in convergence insufficiency of convergence. Without convergence insufficiency, two eyes can work together to see a nearby object. When one has convergence insufficiency, the eyes do not align properly to let one see the up-close item. Doubtless, the vision will be hazy or doubled if one has convergence insufficiency. In the United States, five percent of kids have convergence insufficiency.

• Muscle Weakness: The inability of the eye muscles to control eye movements is referred to as eye muscle weakness.

What Are the Symptoms of Infantile Exotropia?

The symptoms of infantile exotropia are as follows:

• Reduced vision.

• Decreased perception of depth.

• External deviation of the eye.

• Sensitivity to intense light and closing of eyes.

• One or both eyes are outwardly rolling.

• Excessive eye rubbing.

• The act of blinking or shielding one's eyes when seeing strong light or attempting to see in the distance.

• Eye strain caused by close work.

• Inability to read correctly because of diverging eyes.

What Are the Risk Factors for Infantile Exotropia?

• Risk factors include a family history of strabismus, amblyopia, infantile cataracts, or glaucoma.

• Other genetic disorders.

• Some eye conditions, such as pediatric cataracts and glaucoma.

How Is Infantile Exotropia Diagnosed?

Vision tests and a review of the patient's family medical history are the two primary components of the diagnostic process. This condition is best diagnosed by an optometrist or an ophthalmologist, who are both medical professionals that specialize in difficulties relating to the eyes. They will inquire about the symptoms, the medical history of the family, and any other conditions one has to assist them in making a diagnosis. The child's ophthalmologist may recommend the following tests:

• Diagnostic imaging, such as MRI scans, to identify if the eye misalignment is caused by nerve rather than occurring due to muscle problems.

• Genetic tests to identify chromosomal abnormalities that may indicate genetic disorders.

Additional tests include:

• Cycloplegic refraction is used to evaluate the visual acuity of both eyes individually and collectively.

• External or slit lamp test.

• Fundus (retina) analysis.

• Comprehensive eye examination.

How Is Infantile Exotropia Treated?

1. Non-surgical Management: Treatment for amblyopia (a type of strabismus) should include occlusion or penalization, and the patient's refractive defect should be rectified. This is the same recommendation that is made for patients who have any strabismus. Although this is helpful in maintaining the degree of deviation, it is quite improbable that this will lead to the resolution of the exotropia.

• Those with true infantile exotropia that get improvement with dominant eye occlusion therapy are more likely to have early onset intermittent exotropia, a less severe type of the disorder.
• Orthoptics, in particular convergence exercises, can be done. Still, it is unlikely to be successful due to the significant angle of deviation and the fact that the patient's age prevents efficient cooperation with the exercises. Nevertheless, orthoptics can be tried.
• Alternate occlusion therapy as an anti-suppression therapy can be implemented when amblyopia or eye preference is absent.
• Patients with infantile esotropia can correct their nasal and temporal smooth pursuit asymmetry by using long-term alternative occlusion.
• Botulinum toxin injections can be administered to the lateral rectus (LR) muscle as an alternative to surgery. Typically, 2.5 to 5.0 units of Botulinum toxin are administered to each lateral rectus muscle. This method helps reduce the risk of secondary vertical deviation and ptosis, which can occur in conjunction with greater doses or unilateral injections.
• The majority of one's experience with Botulinum is gained through the more prevalent intermittent exotropia, which is laden with the possibility of recurrence. Only a few studies have been conducted on the use of Botox to treat infantile exotropia. Less than half of patients diagnosed with chronic exotropia showed improvement following Botulinum toxin injection into one lateral rectus muscle.

2. Surgical Management: Opinions vary on when to perform surgery on infantile exotropia patients. Indications for surgery:

• Surgery should be considered for infantile exotropia when the tropic (manifest) phase is present at least 50 percent of the time. Serial observations of a rise in the deviation size, a progressive deterioration in the distance and near stereo acuity, a loss of control, and a progressive inability to refuse after manifestation of the deviation suggest damage of control, and surgery should be considered.
• Surgery options include:
  1. Lateral rectus muscle recession.
  2. Recess-resect procedure (lateral rectus muscle recession and ipsilateral medial rectus muscle resection done).
  3. Bilateral medial rectus muscle resection.

Does Exotropia Get Worse as One Gets Older?

If left untreated, exotropia tends to worsen over time. One can deal with it, but it may never go away completely. Some researchers believe that the only long-term solution to the problem of intermittent exotropia is to be able to repair the brain, which is currently not possible.

How Can One Prevent Exotropia?

Exotropia cannot be prevented.

Conclusion:

Exotropia is common and curable, especially when caught early and treated. The eyes should be in alignment and capable of focusing by the age of four months. After this point, one must consult an eye doctor if still noticing misalignment. Exotropia rarely spontaneously improves when left untreated, according to experts. Instead, it tends to get worse over time; one can react quickly to get treatment. Even though one cannot do much to stop it from happening, one can respond quickly to get treatment for it.