Exotropia (Outward Turning Eyes)

What is Exotropia (Eyes Turning Outward)?

Exotropia refers to a type of strabismus (eye misalignment) in which either one or both of the eyes turn outward. It is not the same as esotropia, in which either one or both of the eyes turn inward. 

Exotropia is a common condition. It comprises 25% of all ocular misalignment cases in young children. While it could happen periodically (e.g., intermittent exotropia), it could also be constant. 

However, it is more typical to find exotropia developed while a child is 1 to 4 years old. Parents may notice this form of strabismus, especially when the child is daydreaming, sick, or tired. 

It may also be apparent when the child attempts to focus on distant objects. Conversely, when a child focuses on items up close, it may be difficult to notice the eye condition. 

If there is suspicion of exotropia, it is important to seek an eye care specialist. An eye doctor can perform a comprehensive eye exam and differential diagnosis to rule out other possible conditions. 

Different Types of Exotropia

Exotropia can be classified into different subsets. Speaking with your ophthalmologist and undergoing an eye exam can help determine which type of exotropia you or your child has.  

Sensory Exotropia

If a person has sensory exotropia, the eye may suffer from poor vision or blindness. It will also turn outward. 

Initially, if an infant or young child has a blind or poorly seeing eye, esotropia (cross-eyes) develops. However, in older children (between the ages of 2 and 4 years), the eye often becomes exotropic. 

Intermittent Exotropia

With intermittent exotropia, one eye turns outward on occasions. Other times, the eyes are straight, and there is no apparent indication of the condition. Family members or friends may observe the exotropia when the person with the condition is either tired or daydreaming. 

Also, intermittent exotropia may be more noticeable when the person looks at distant objects. 

While it is rare and will cause no to few symptoms, intermittent exotropia can occur more often or progress to becoming constant. 

Congenital Exotropia

Some may refer to congenital exotropia as infantile exotropia. This outward turning of the eyes is present since birth or during early infancy. 

While esotropia is more common in infants, a pediatric ophthalmologist should evaluate constant exotropia. The latter condition may be associated with an underlying medical condition. 

Alternating Exotropia 

As the name suggests, people with an alternating exotropia have an outward eye turn that alternates both eyes. The condition can be constant or intermittent and vary in degree of severity. 

Intermittent exotropia is the most frequent type of strabismus, impacting as much as 1% of the U.S. population. It is more common in females than in males. 

What Causes Exotropia?

There is no specific, known cause of exotropia. 

However, exotropia may be common in children with either sensory exotropia or an underlying genetic disorder that impacts eye movements. 

Here is a list of some diseases that could increase the likelihood of developing exotropia:

• Duane’s syndrome —  this is a congenital strabismus syndrome, in which people with the condition could experience diplopia (double vision), anisometropia (the two eyes have different refractive errors), and amblyopia (lazy eye). 
• Slipped or lost medial rectus muscle — loss of this muscle can happen after different types of eye surgery, including retinal detachment surgery or paranasal sinus surgery. 
• Internuclear ophthalmoplegia — this is an ocular motility disorder that impairs the lateral gaze and causes ophthalmoplegia (paralysis or weakness of the eye muscles). 
• Orbital fibrosis — this rare condition is characterized by an infiltrating orbital mass and thickening of connective tissue. 

Additionally, having some of the risk factors below may raise the probability of exotropia:

• Family history of strabismus, amblyopia, childhood cataract, or glaucoma (increased eye pressure). 
• Some genetic disorders, such as cerebral palsy or Down syndrome 
• Childhood cataracts or glaucoma

It is important to distinguish that exotropia is not a disease in and of itself. This condition refers to a motility disturbance (abnormal eye movements or trouble in managing eye movements). It can occur as a result of a particular medical disease or disorder. 

Signs & Symptoms of Exotropia

Those with exotropia may experience some symptoms of exotropia or show signs. For example, they may have:

• Loss of binocular vision
• Loss of depth perception
• Outward deviation of the eyes (can begin as intermittent)
• Eyestrain
• Sensitivity to bright light or bright sunlight (causing them to squint) 

While these symptoms do not always indicate exotropia, it is important to seek an eye consultation if one or more of these symptoms are present. 

Is it Possible to Outgrow Intermittent Exotropia?

Intermittent exotropia may occur in infants as young as 1 to 2 months of age. If the condition is mild, it may go away on its own within 6 to 8 weeks of birth. 

In other cases of exotropia, it is not common to find a complete resolution of the condition. While patching, glasses, or vision therapy can help, exotropia may remain present. 

Potential Complications of Exotropia

Exotropia can cause complications, including:

• Headaches
• Trouble reading 
• Eyestrain

• Blurry vision
• Decreased 3D vision
• Abnormal head posture

According to the American Journal of Ophthalmology, more than 90% of children with intermittent exotropia studied would develop myopia by 20 years of age.

How is Exotropia Diagnosed?

An eye doctor, such as an ophthalmologist or optometrist, will perform an exotropia diagnosis based on family history, symptoms, and vision testing. 

Vision tests can consist of:

• Reading letters from an eye chart 
• A refraction to test for uncorrected refractive error, in which case glasses may be prescribed
• Eye drops that dilate the pupils of the eyes and facilitate examination of the eyes’ internal structures

Treatment Options for Exotropia

Those with exotropia can explore both non-surgical and surgical treatment options. 

Non-surgical treatment possibilities include:

• Patching 
• Over-minused spectacles or glasses
• Orthoptic therapy (these exercises will facilitate the re-education of binocular vision)
• Prism glasses 

Surgical treatments may be performed to maintain or restore binocular capability. It may also help provide relief for diplopia (double vision) or cosmesis (to enhance physical appearance). There is a higher success rate in the long run for those with intermittent exotropia and with stronger binocular function at the time of surgery. 

To determine which treatment is most suitable, you should visit your local eye clinic and speak with a professional eye care specialist.