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Intermittent Exotropia: Causes, Symptoms, Diagnosis, and Treatment
Intermittent exotropia is a type of strabismus in which one of the eyes turns outwards, towards the ears, on an occasional, non-constant basis. Exotropia strabismus, specifically intermittent exotropia, is one of the most common forms of strabismus. Intermittent exotropia is caused by an issue with the muscles in the eye, though the reason these issues occur is not conclusively known. The symptoms of intermittent exotropia can include eye strain or headaches, abnormal outward eye movement, double vision, excessive blinking, squinting in sunlight and eye deviation during illness, fatigue or daydreaming. Intermittent exotropia will be diagnosed by an optometrist or another eye care professional using tests such as a slit lamp test and a visual acuity test. Treatment for intermittent exotropia can include prescription glasses, eye exercises, eye patching and surgery.
What is Intermittent Exotropia?
Intermittent exotropia is the most common type of strabismus, characterised by an occasional outward turning or outward deviation of one of the eyes, according to Kaur K, and Gurnani B in their paper Intermittent Exotropia. Exotropia refers to strabismus in which one or more eyes turn outwards. Intermittent exotropia occurrence is different to general exotropia as it does not occur all the time. Intermittent exotropia occurrence is dependent upon the individual but may happen at irregular intervals, with the eye more likely to turn or deviate when a person is under stress, is tired, is sick, daydreaming, or looking into the distance, according to the Cleveland Clinic. Other times the eyes may be in alignment. Intermittent exotropia commonly affects children but can also occur in adults.
What is the Other Term for Intermittent Exotropia?
The other terms for intermittent exotropia are intermittent squint, divergent squint and strabismus. Intermittent exotropia may be known by the term strabismus, or squint, which is an umbrella term for eyes that are not in alignment with each other. Intermittent exotropia may also be known as a divergent squint, according to the NHS.
What Does Intermittent Exotropia Look Like?
Intermittent exotropia will generally look like an eye that has turned or deviated out of straight alignment towards the ear. The image below shows what eyes in normal alignment look like, compared to an eye that has intermittent exotropia that has turned towards the ears.
What Causes Intermittent Exotropia to Happen?
There is no exact intermittent exotropia cause. Strabismus, including exotropia, occurs due to the issues with the muscles in the eye, although what causes these issues is not conclusively known. Exotropia strabismus has been theorised to be caused by poor vision in one eye, or be associated with medical conditions that affect the eyes, according to the Kellogg Eye Centre. It is important that a person seeks advice from an optometrist or eye care professional if they believe they have intermittent exotropia.
What Muscle is Involved in Intermittent Exotropia?
Intermittent exotropia is caused by issues with the eye muscles, which may specifically involve the inferior oblique muscles. According to Pang, Gnanaraj, Gayleard, Han, and Hatt in their paper Interventions for intermittent exotropia, an overreaction of the inferior oblique muscle may play a role in intermittent exotropia.
How Common is Intermittent Exotropia?
Intermittent exotropia is often cited as the most common form of strabismus. According to the American Academy of Ophthalmology, intermittent exotropia makes up 75 - 90% of exotropia cases. According to an article by Optometry Australia, 1 in 50 children have intermittent exotropia.
Is Intermittent Exotropia Hereditary?
Yes, intermittent exotropia can be hereditary or run in families as can most forms of strabismus. According to the American Association for Pediatric Optometry, the type of strabismus and the severity of the condition may not be the same for all family members with strabismus. A study discussed in the paper Strabismus genetics across a spectrum of eye misalignment disorders, posits that esotropia, a type of strabismus in which the eye or eyes are deviated towards the nose, is more likely to have a genetic cause than exotropia.
Is Intermittent Exotropia a Disability?
Intermittent exotropia may be considered a disability or visual impairment depending on the severity of the condition. According to the Australian Family Physician, people with strabismus may have functional and psychosocial problems as a result of strabismus that is severe. Strabismus that is severe in nature and left untreated can lead to difficulties during everyday life. It is important that you see an optometrist or eye care professional if you believe you have exotropia so the condition can be treated.
Is Intermittent Exotropia a Disease?
No, intermittent exotropia is not considered a disease, but rather an eye condition or visual disorder. Intermittent exotropia is characterised by an eye that is turned or deviates outwards, towards the ear in a non-constant manner. Eye diseases are more commonly considered to include conditions such as glaucoma, dry eye disease and age-related macular degeneration.
How Does Intermittent Exotropia Differ from Other Types of Exotropia?
Intermittent exotropia differs from other types of strabismus in the way the eyes turn or deviate, and from other types of exotropia strabismus in how often the eye turning occurs. Exotropia strabismus is characterised by the eye or eyes turning outwards. Esotropia is a type of strabismus where the eyes turn inwards. Hypertropia is characterised by the eye turning upwards and hypotropia is characterised by an eye or eyes that turn downwards. Intermittent exotropia differs from the other types of exotropia in how often it occurs, with the eye turning not always present, and often only present when a person is stressed, tired, daydreaming, or has been focusing on something in the distance.
Is Intermittent Exotropia the Most Common Type of Strabismus?
Yes, intermittent exotropia is considered one of the most common types of strabismus. Exotropia is one of the most common types of strabismus, occurring in 25% of ocular misalignment cases in children, according to the Kellogg Eye Centre. Intermittent exotropia makes up 75-90% of exotropia cases, according to the American Academy of Ophthalmology.
What are the Symptoms of Intermittent Exotropia?
The symptoms of intermittent exotropia may vary depending on the severity of the condition but may include eye strain or headaches, abnormal outward eye movement, double vision, excessive blinking, eye deviation during illness, fatigue or whilst daydreaming and squinting in sunlight. The possible symptoms of intermittent exotropia are listed below.
- Eye strain or headaches: Intermittent exotropia may cause eye strain or headaches as the eyes are not in alignment which can make focusing difficult and put strain on the eyes.
- Abnormal outward eye movement: Abnormal outward eye movement that comes and goes is the most common symptom of intermittent exotropia.
- Double vision: Double vision may be a symptom of intermittent exotropia as the eyes will not be in alignment, making it difficult for the eyes to see one image of the same object.
- Excessive blinking: Excessive blinking may be a symptom of intermittent exotropia as it can be a way for people to help correct eye turning.
- Eye deviation during illness, fatigue, or daydreaming: Eye deviation when a person is ill, fatigued or daydreaming is a common symptom of intermittent exotropia.
- Squinting in sunlight: Squinting in sunlight or any bright light can be a symptom of intermittent exotropia as bright light may trigger an eye turn, causing people with this eye condition to squint against bright light to prevent a turn from occurring.
1. Eye Strain or Headaches
Eye strain and headaches resulting from eye strain may be symptoms of intermittent exotropia. Intermittent exotropia is characterised by the eye or eyes turning outwards towards the ears. As the eyes are not in alignment, intermittent exotropia can make focusing the eyes difficult, leading to eye strain and possibly headaches as a result of this eye strain. Eye strain refers to the eyes straining or overworking to see an object and keep it in focus. Eye strain can lead to issues such as headaches and sore eyes.
2. Abnormal Outward Eye Movement
Abnormal outward eye movement is the main symptom of intermittent exotropia. Abnormal outward eye movement refers to the eye or eyes turning or deviating outwards, towards the ears. Abnormal outward eye movement is the most common and telling symptom of intermittent exotropia. Abnormal outward eye movement in the case of intermittent exotropia may not always be present, most often occurring if a person is tired, sick, daydreaming or focusing on objects far away.
3. Double Vision
Double vision may be a symptom of intermittent exotropia due to the way the eyes are misaligned. Double vision, also known as diplopia, refers to seeing two images of the same object. Double vision may occur as a result of intermittent exotropia as the eyes will not be in alignment if one is turned outwards, making it hard for the eyes and the brain to see one image of the same object.
4. Excessive Blinking
Excessive blinking may be a symptom of intermittent exotropia as blinking may be used by people with this eye condition as a way to try and correct the eye turn and realign the eyes. In a study conducted by Hatt, Leske and Holmes, blinking was reported as a way for people with intermittent exotropia to correct their eye deviation and bring the eyes back into alignment with each other, which may account for why those with intermittent exotropia blink more than usual.
5. Eye Deviation During Illness, Fatigue, or Daydreaming
Eye deviation during illness, when fatigued or when daydreaming is a common symptom of intermittent exotropia. If a person has intermittent exotropia, this means that their eye or eyes will turn towards the ears on an infrequent basis. If a person is ill, fatigued, daydreaming, as well as anxious, stressed or focused for a prolonged time, the eyes are more likely to deviate.
6. Squinting in Sunlight
Squinting in sunlight or any bright light can be a symptom of intermittent exotropia. According to the Kellogg Eye Centre, bright light such as sunlight can trigger eye turning if a person has intermittent exotropia. People with intermittent exotropia may squint their eyes if in sunlight or bright light to prevent this light from triggering the eyes to turn.
How Do Eye Doctors Diagnose Intermittent Exotropia?
In Australia, an eye doctor is a medical professional that specialises in eye care, called an ophthalmologist and may be involved in the diagnosis and treatment of exotropia, as will an optometrist. Optometrists are qualified and trained to diagnose a range of conditions including exotropia. Intermittent exotropia can be diagnosed through visual acuity, refraction test and an eye alignment and focus assessment according to Cleveland Clinic. Your eye care professional may also ask you about your family’s medical history.
How Serious is Intermittent Exotropia?
Intermittent exotropia may lead to serious vision issues if left untreated. According to the Cleveland Clinic, intermittent exotropia that is left untreated may lead to amblyopia also known as lazy eye, which is reduced or poor vision in one eye. Untreated intermittent exotropia may also lead to issues with binocular vision and depth perception.
Is Intermittent Exotropia contagious?
No, intermittent exotropia is not contagious, it is an eye muscle issue that cannot be transferred to other people. Intermittent exotropia may be hereditary or caused by vision issues and medical conditions.
What are the Potential Complications of Intermittent Exotropia?
The complications of intermittent exotropia are associated with eye surgery, according to an article published in the National Library of Medicine. These complications are categorised into anaesthesia-related and surgical complications which are further divided into intraoperative and postoperative. Anaesthesia-related complications include oculocardiac reflex and malignant hyperthermia, intraoperative include globe perforation and lost or slipped muscle and postoperative include diplopia (double vision) and retinal detachment. These complications are very serious which is why surgery is something that needs to be discussed with your healthcare provider and your surgery recovery needs to be monitored.
How Long Does Intermittent Exotropia Last?
How long intermittent exotropia lasts is dependent upon the individual, the severity of their intermittent exotropia and what treatment is being given for the condition. According to the University of Iowa, not all intermittent exotropia cases will get progressively worse, some may remain stable and some may improve with treatment.
How is Intermittent Exotropia Treated?
Intermittent exotropia treatment can be categorised into non-surgical and surgical. Non-surgical treatments include prescription glasses for refractive errors, part-time eye patching and eye exercises according to an article published in the National Library of Medicine. Prescription glasses are used to correct refractive errors and can treat intermittent exotropia by helping the wearer regain control of their misaligned eyes. Part-time eye patching is often used for young children and works by helping the patient improve their control of eye deviation. Eye exercises to treat intermittent exotropia include pencil push-ups which train the eyes to focus on a single point. Surgery for intermittent exotropia can include unilateral and bilateral and is performed to restore binocular function which means seeing a single image with both eyes.
How Long Does it Take to Treat Intermittent Exotropia?
It is difficult to determine how long it takes to treat intermittent exotropia as it depends on the patient and other factors such as age and the type of treatment prescribed.
Can Intermittent Exotropia be Cured Without Surgery?
Yes and no, intermittent exotropia may be cured on its own without surgery depending on the severity and the age the condition was developed. According to the American Association for Pediatric Ophthalmology and Strabismus, intermittent exotropia symptoms may be managed with prescription glasses and non-surgical methods.
Do Glasses Fix Intermittent Exotropia?
Yes and no, glasses may fix intermittent exotropia if the patient experiences high astigmatism or nearsightedness as it can aid in the alignment of the eyes. However, glasses may not be capable of completely fixing exotropia as it depends on factors such as the severity of the condition and the age of the patient when the intermittent exotropia began.
Can Intermittent Exotropia Go Away on Its Own?
Yes, according to the Cleveland Clinic, intermittent exotropia may go away on its own or is mild enough that it does not require treatment. Intermittent exotropia is characterised by it not being present all the time, therefore, it often goes away on its own but will likely come back when a person is sick or tired. While this type of strabismus may go away on its own, it is important to have your eyes assessed by an optometrist if you believe you have intermittent exotropia.
Can Lasik Fix Intermittent Exotropia?
No, Lasik, or laser-assisted in situ keratomileusis, cannot fix intermittent exotropia or any other eye muscle issues. Lasik is used to treat refractive errors such as astigmatism, myopia and hyperopia, not types of strabismus. Intermittent exotropia can be treated with eye muscle surgery which changes the length and position of a person’s eye muscles, which corrects the eye’s misalignment.
What Type of Strabismus Eye Exercise Helps Fix Intermittent Exotropia?
The type of eye exercises that may help treat intermittent exotropia, a type of strabismus, include patching part-time and pencil push-ups, according to an article published in Optometry Advisor. Patching is more a treatment than an eye exercise but it is commonly suggested for children with strabismus. Pencil push-ups are a type of eye exercise that helps train the eyes to focus on a single point. This eye exercise for strabismus is performed by holding a pencil in front of the face, an arm’s length away. Focus on the pencil and slowly move it towards your face while trying to keep the pencil as one image.
