Understanding Intermittent Exotropia
What Is Intermittent Exotropia
With intermittent exotropia, the eye does not stay turned out all day long. You or your child may look perfectly aligned most of the time, especially when concentrating on a nearby task like reading or playing a game. The outward drift appears and disappears, often without any conscious control.
Many parents first notice the eye turn in photographs or when their child is looking at something far away. Between these episodes, the eyes work together normally, and the alignment looks straight.
A constant eye turn, or tropia, is visible all the time, whether the person is tired or alert. Intermittent exotropia is different because the eyes can hold alignment for periods throughout the day. The brain is still able to use both eyes together much of the time, which helps preserve depth perception.
Because the misalignment is not always present, intermittent exotropia can be harder to detect at first. Parents may wonder if they imagined the eye turn or if it was just a trick of the light.
Certain situations make the outward drift more likely to appear. Bright sunlight is a classic trigger, and many children will squint or close one eye when stepping outside on a sunny day. Daydreaming, staring into space, or looking at distant objects also tend to bring out the eye turn.
- Fatigue or illness
- Bright outdoor light or glare
- Looking at faraway objects
- Relaxed or unfocused states, such as watching television
The muscles that keep the eyes aligned can become tired, just like any other muscle in the body. As the day progresses, it takes more effort for the brain to hold the eyes together. By late afternoon or evening, the eye may drift outward more frequently or for longer periods.
This pattern of worsening symptoms with fatigue is one of the hallmarks of intermittent exotropia. Restful sleep often allows the eyes to realign more easily the next morning.
Recognizing the Signs of Intermittent Exotropia
The most obvious sign is seeing one eye drift toward the ear while the other stays focused straight ahead. This often happens when the person is not actively concentrating, such as during quiet moments or when zoning out. The eye may snap back into place when the person is called or becomes alert again.
Some children develop habits to hide the drift, like tilting their head or avoiding eye contact. These behaviors can be subtle clues that the eyes are not working together consistently.
Closing one eye outdoors is a very common sign of intermittent exotropia. Bright light can make it harder for the brain to fuse the images from both eyes, triggering the outward drift. Shutting one eye eliminates the double vision or confusion that might result.
If your child frequently closes one eye outside but not indoors, we recommend scheduling an eye exam. This behavior often signals an underlying eye alignment issue.
When the eye drifts, the brain receives two separate images that do not line up. Some people notice this as double vision, especially when the eye first starts to turn. Others describe things looking blurry or unclear, even though their glasses prescription is correct.
- Seeing two of the same object side by side
- Headaches after reading or screen time
- Eye strain or discomfort
- Difficulty switching focus between near and far
Good depth perception depends on both eyes working as a team. When one eye drifts out, the brain may struggle to judge how far away objects are. Children with intermittent exotropia may bump into things, misjudge steps or curbs, or have trouble with ball sports that require accurate depth cues.
These coordination challenges can affect everyday activities like pouring a drink, catching a ball, or navigating crowded hallways. Noticing these patterns can help parents and teachers recognize a possible vision problem.
When an eye drifts outward, the brain may learn to ignore the image from that eye to avoid double vision. This is called suppression.
Although amblyopia is less common in intermittent exotropia than in constant strabismus, some children can develop reduced vision in one eye. Regular exams allow us to detect suppression or amblyopia early and treat it promptly.
While intermittent exotropia itself is not usually an emergency, sudden changes in eye alignment should be evaluated promptly. If an eye that was previously straight suddenly turns outward all the time, or if the eye turn is accompanied by severe headache, vomiting, or vision loss, we recommend urgent evaluation to rule out other conditions.
Any new onset of double vision in adults or a sudden increase in the frequency of the eye turn also warrants a timely exam. These changes can sometimes signal other health issues that need attention.
- New droopy eyelid, unequal pupils, or new limitation of eye movements
- Recent head or eye trauma
- Painful, red eye with vision changes
- New constant double vision in adults or double vision that does not go away when one eye is covered
Risk Factors and Causes
Intermittent exotropia tends to run in families. If a parent or sibling has had an eye turn, the risk is higher for other family members. The condition is not always inherited in a simple pattern, but a family history is one of the strongest predictors.
We often ask about relatives who wore glasses as children, had eye surgery, or were told they had lazy eye or strabismus. These details help us understand your risk profile and the likelihood that your child may develop the condition.
Each eye is controlled by six small muscles that move it in different directions. The brain sends signals to these muscles to keep both eyes pointed at the same target. In intermittent exotropia, the brain has trouble maintaining that coordination consistently, and one eye drifts outward when control weakens.
- The lateral rectus muscle pulls the eye outward
- The medial rectus muscle pulls the eye inward
- Balance between these muscles keeps the eye centered
- Fatigue or relaxation can tip the balance and allow the drift
Some children with intermittent exotropia also have refractive errors such as myopia, anisometropia, or astigmatism. Uncorrected vision problems can make it harder for the eyes to stay aligned, especially during tasks that require sustained focus. Correcting the refractive error with glasses can sometimes reduce the frequency or severity of the eye turn.
We always check for nearsightedness, farsightedness, and astigmatism as part of the comprehensive exam. Even a small prescription can make a difference in eye alignment for some patients.
In selected children, a small minus lens overcorrection (overminus lenses) can improve distance control by stimulating accommodative convergence. This is usually a short term strategy and requires close monitoring for possible myopic shift.
Several other factors can increase the risk of intermittent exotropia or may be associated with the condition.
- Prematurity or low birth weight
- Anisometropia or large differences in prescription between eyes
- Decreased vision in one eye from any cause, leading to sensory exotropia
- Neurologic or developmental conditions
- Craniofacial syndromes
- Thyroid eye disease in adults
Most cases of intermittent exotropia develop in early childhood, often between the ages of one and five years. Parents may notice the eye turn becoming more obvious as the child grows and becomes more active. However, the condition can also be diagnosed later in childhood or even in teenagers and adults who were never evaluated as children.
Early detection is helpful because it allows us to monitor the condition and intervene if the eye turn worsens over time. Regular eye exams during the preschool and school years help catch intermittent exotropia before it affects learning or development.
How We Test for Intermittent Exotropia
We start by asking about your symptoms, when you notice the eye turn, and any family history of eye problems. Then we check your vision with and without glasses, and we look at the health of the inner and outer structures of your eyes. The alignment testing is a key part of the exam and involves several specialized techniques.
Most tests are comfortable. In children and many adults we use dilating and cycloplegic eye drops to accurately measure refractive error and examine inside the eye. The drops may sting briefly and cause temporary light sensitivity and near blur.
- Cycloplegic refraction to measure the full glasses prescription
- Cover-uncover and prism and alternate cover testing at distance and near
- Measuring control with an office scale or the Newcastle Control Score
- Distance and near stereoacuity testing
- Worth 4 Dot or similar tests to check for suppression
- Near point of convergence and fusional convergence amplitudes
- Assessing AC/A ratio when relevant
- A brief patch test to reveal the full deviation if needed
The cover test is the gold standard for diagnosing eye misalignment. We ask you to look at a target, then we cover one eye and watch how the uncovered eye moves. If it shifts inward to pick up the target, that tells us the eye was drifted outward before we covered the other eye.
- We repeat the test at different distances
- We measure the size of the drift in prism diopters
- We observe how quickly the eye drifts after we remove the cover
- We test with and without glasses if you wear them
We also perform a prism and alternate cover test and may reassess control after brief occlusion to reveal the full deviation.
Good depth perception requires both eyes to work together. We use special tests, such as the stereo fly test, to measure how well your eyes team up. In this test, you wear polarized glasses and look at images that appear three-dimensional only if both eyes are aligned and working as a team.
People with intermittent exotropia often have normal or near-normal depth perception when their eyes are aligned, but it can drop significantly when the eye drifts. Tracking these changes helps us decide on the best treatment plan. We may also use the Worth 4 Dot test and distance stereo tests to detect suppression that can appear when the eye drifts.
Because the eye turn comes and goes, we try to observe it under conditions that make it more likely to appear. We may dim the lights, ask you to look at a distant target, or have you relax and daydream for a moment. We also ask parents to take photos or videos at home when they see the drift, which can be very helpful for diagnosis.
Sometimes the eye turn is so well controlled during the exam that we do not see it at all. Home documentation and a detailed history become even more important in those cases.
Treatment Approaches for Intermittent Exotropia
Not every case of intermittent exotropia requires immediate treatment. If the eye turn is small, happens infrequently, and does not cause symptoms like double vision or poor depth perception, we may recommend regular monitoring instead of intervention. Many children maintain good control of their eye alignment for years with observation alone.
During the observation period, we schedule follow-up exams every few months to a year, depending on the situation. We watch for signs that the condition is worsening, such as the eye turning out more often or the drift becoming larger.
If you have an uncorrected refractive error, wearing the right glasses can sometimes improve eye alignment. In some cases, we may prescribe a small minus lens overcorrection (overminus lenses) to stimulate accommodative convergence and improve distance control. This approach can help children with good focusing ability and requires monitoring for possible myopic shift.
- Glasses correct blurry vision and reduce eye strain
- A precise prescription supports better eye teaming
- Glasses alone may not eliminate the drift but can reduce its frequency
- We monitor progress with follow-up exams
Vision therapy is a personalized program of eye exercises designed to improve the coordination between the eyes and the brain. For intermittent exotropia, therapy may focus on convergence exercises, which train the eyes to turn inward and hold that alignment. These exercises are done both in the office with our guidance and at home as part of a daily routine.
Vision therapy can be helpful for patients with convergence insufficiency or small to moderate intermittent exotropia who want to improve control and reduce symptoms. It does not typically reduce a large-angle deviation. Success depends on consistent practice and motivation, and results vary from person to person.
Patching one eye for part of the day can be used in younger children to temporarily improve control or to treat amblyopia if present. Prism glasses can reduce the effort needed to keep the eyes together or relieve double vision for small angles. These options help manage symptoms but do not cure intermittent exotropia.
Prisms can be especially useful if you experience double vision when the eyes are trying to align. They provide temporary relief while we consider longer-term solutions.
Surgery is the most common and effective treatment for intermittent exotropia that is worsening or causing symptoms. The procedure adjusts the tension of the eye muscles to help the eyes stay aligned more easily. We typically operate on one or both eyes, depending on the size and pattern of the drift.
Common procedures include bilateral lateral rectus recessions or a recession-resection on one eye. In adults, adjustable sutures may be used to fine tune alignment after surgery.
Timing is important. We usually recommend surgery if the eye turn is present more than half the time, if it is getting larger, or if depth perception is declining. Eye muscle surgery is generally safe and is performed as an outpatient procedure under general anesthesia for children or with local anesthesia and sedation for some adults.
As with any surgery, there are risks. These include undercorrection or overcorrection, need for additional surgery, infection, scarring, persistent or new double vision, slipped muscle, very rare scleral perforation, anterior segment ischemia in high-risk multi-muscle cases, and anesthesia risks.
Most people go home the same day as surgery and return to normal activities within a week or two. The eye may be red and sore for several days, and we prescribe eye drops to reduce inflammation and prevent infection. We see you back in the office within a few days and then monitor your alignment over the following months.
- The goal is to achieve straight eyes most or all of the time
- Some patients may have a small residual drift or need a second surgery
- Improved alignment often leads to better depth perception and fewer symptoms
- Long-term follow-up is important to catch any changes early
- Avoid swimming and submerging the eyes for 1 to 2 weeks
- Use sunglasses if light sensitivity occurs while the drops are in effect
- Reading and screens are allowed as comfort permits
- Some early double vision is common while the brain adapts
- Alignment can change over months or years, and some drift can return over time
Living with and Managing Intermittent Exotropia
If we recommend vision therapy, you will practice specific exercises at home to reinforce what you learn in the office. Common exercises include pencil push-ups, where you focus on a small target as it moves closer to your nose, and Brock string exercises, which help train convergence. Consistency is key, and even a few minutes each day can make a difference.
We will teach you the correct technique and give you clear instructions on how often to practice. Keeping a log of your exercises helps us track your progress and adjust the program as needed.
Because fatigue can worsen the eye turn, getting enough sleep and taking breaks during visually demanding tasks can help. We recommend the 20-20-20 rule: every 20 minutes, look at something 20 feet away for 20 seconds. This gives your eye muscles a chance to relax and reduces the risk of the drift appearing.
- Limit screen time, especially before bed
- Ensure good lighting when reading or doing homework
- Encourage outdoor play and distance viewing
- Maintain a regular sleep schedule
- Use a brimmed hat or sunglasses outdoors if bright light triggers the drift
After eye muscle surgery, follow all post-operative instructions carefully. Use the prescribed eye drops as directed, avoid rubbing the eyes, and keep water out of the eyes for the first week. You can expect some redness, mild discomfort, and possibly double vision for a few days as the eyes adjust to their new alignment.
Contact our office right away if you notice severe pain, vision loss, excessive discharge, or any other concerning symptoms. Most people heal smoothly and see significant improvement in eye alignment within the first few weeks.
Whether you choose observation, glasses, vision therapy, or surgery, regular follow-up is essential. We need to track how your eyes respond to treatment and watch for any changes over time. Intermittent exotropia can evolve, and what works today may need adjustment in the future.
We will create a follow-up schedule tailored to your situation. For children, exams may be more frequent during periods of rapid growth or after treatment changes. Adults with stable intermittent exotropia may need less frequent monitoring, but annual exams are still a good idea.
Frequently Asked Questions
Intermittent exotropia rarely goes away on its own, and most children do not outgrow the condition. In fact, the eye turn often becomes more frequent or larger as a child gets older. Early diagnosis and appropriate management can prevent the condition from worsening and help maintain good depth perception and visual function.
Yes, intermittent exotropia can progress, especially if left untreated. The eye may start drifting more often, the size of the drift may increase, and the person may have more difficulty pulling the eye back into alignment. This is why we emphasize regular monitoring so we can intervene at the right time if the condition deteriorates.
Surgery is not always required. Some people with mild, infrequent eye turns do well with observation or non-surgical treatments like glasses or vision therapy. However, if the exotropia becomes constant, causes symptoms, or affects quality of life, surgery is often the most reliable way to restore lasting alignment and preserve binocular vision.
Intermittent exotropia can impact activities that rely on depth perception, such as catching a ball, judging distances, or reading a whiteboard from across the room. Some children may struggle with eye strain or headaches that make schoolwork harder. Treating the condition often improves comfort and performance in both academic and athletic settings.
Most cases begin in childhood, but adults can develop intermittent exotropia, especially if they had a small, unnoticed drift as a child that worsens with age. New onset exotropia in adulthood can also be a sign of other neurological or health issues, so a comprehensive evaluation is important if an adult notices a sudden change in eye alignment.
Eye muscle surgery is effective for many patients with intermittent exotropia, with most people achieving improved alignment and fewer symptoms. Some people may need a second procedure if the eyes overcorrect or undercorrect, but overall outcomes are very favorable. Success is measured not just by straight eyes, but also by improvements in depth perception, comfort, and quality of life. Some degree of drift over time is common, and periodic follow-up helps decide if further treatment is needed.
Getting Help for Intermittent Exotropia
If you or your child shows signs of an eye turn, we encourage you to schedule a comprehensive eye exam. Early evaluation allows us to diagnose intermittent exotropia, monitor its progression, and recommend the most effective treatment when needed. Our goal is to help you maintain healthy, comfortable vision and the best possible eye alignment for a lifetime.