Intermittent exotropia- things you should know about this condition

Intermittent exotropia is a common type of eye misalignment (strabismus) where one or both eyes tend to drift outward, particularly when focusing on distant objects or when a person is fatigued. This condition, often seen in children, can affect visual development if left untreated. Early detection and treatment are essential to prevent further complications in vision. Tropia is menifest deviation of the eye in which the eye is misaligned from the centre.

Intermittent exotropia- menifest deviation

Unlike constant exotropia, intermittent exotropia occurs sporadically, meaning that the eyes may align properly most of the time but occasionally deviate outward which is more noticeable when the individual is tired, stressed, or daydreaming and can be triggered by focusing on distant objects.

Symptoms

Identifying the symptoms of intermittent exotropia early is crucial, especially in children, as it can impact their vision development. Here are some common symptoms

Outward Deviation of One Eye: A noticeable outward drifting of one or both eyes, especially when looking at distant objects.

Frequent Squinting or Closing One Eye: This is particularly noticeable in bright sunlight or when the person feels visual discomfort.

Double Vision (Diplopia): Some individuals may experience double vision during the episodes of eye misalignment.

Difficulty with Eye Tracking: Struggling to follow objects smoothly may indicate an issue with eye coordination.

Visual Discomfort: Some people with intermittent exotropia report headaches or eye strain, especially when reading or doing close work for extended periods.

Onset factors

The exact cause of intermittent exotropia is not always clear. However, some factors that can contribute to this condition include:

1. Genetic Factors: A family history of strabismus or eye alignment issues can increase the risk of developing intermittent exotropia.
2. Refractive Errors: Individuals with uncorrected refractive errors, such as myopia (nearsightedness), may be more prone to eye misalignment.
3. Eye Muscle Imbalance: Weakness or poor coordination between the muscles that control eye movement can lead to intermittent exotropia.
4. Nervous System Factors: Neurological issues affecting the control of eye movements can sometimes contribute to the development of intermittent exotropia.

Muscles involved

Intermittent exotropia typically involves issues with the extraocular muscles that control eye movement, specifically the lateral rectus and medial rectus muscles.

Diagnosis and investigation

Diagnosing intermittent exotropia typically involves a comprehensive eye examination. Here’s what to expect during the diagnosis process:

1. Detailed history taking: Chief complain, histroy of spectacles, surgey, deviation, general health, birth and trauma history etc.
2. Visual Acuity Test: To assess the sharpness of vision in each eye.
3. Cover-Uncover Test: A cover test helps the optometrist detect misalignment by covering one eye and observing the movement of the uncovered eye.
4. Alternate Cover Test: This test helps to assess the severity of misalignment by alternately covering each eye.
5. Prism reflection test and Krimsky test to measure deviations
6. Prism tests to measure the fusional ranges
7. Ocular Motility Test: This is used to evaluate how well the eyes move in various directions.
8. Refraction Test: To detect any refractive errors that may be contributing to the condition.

Other supporting tests may include the tests to check the stereopsis, fusion and suppression of the eyes e.g. Lang pencil test, Frisby test and Worth’s four dot test respectively.

Treatment for intermittent exotropia

Treatment for intermittent exotropia aims to improve eye alignment, prevent vision problems, and enhance eye coordination. The choice of treatment depends on the frequency and severity of the eye deviation. Here are some common treatment options:

1. Observation and Monitoring

• If the condition is mild and infrequent, doctors may recommend regular monitoring. Parents are often advised to observe if symptoms worsen over time.

2. Corrective Lenses

• Glasses with the appropriate prescription may help reduce the frequency of eye deviation, especially if a refractive error like myopia is present.

3. Vision Therapy

• Vision therapy exercises can help improve eye coordination and control. These exercises can be done at home or in a clinical setting under professional supervision.
• Eye exercises such as “pencil push-ups” (bringing a pencil close to the nose while keeping it in focus) may be prescribed to strengthen convergence (eye-turning ability).

4. Prism Lenses

• Prisms are sometimes incorporated into eyeglasses to help the eyes align better, reducing the occurrence of eye drifting.

5. Surgical Intervention

• In cases where intermittent exotropia becomes frequent or severe, eye muscle surgery may be recommended to realign the eyes. This surgery involves adjusting the length or position of specific eye muscles to improve alignment.

Prognosis and Long-Term Outlook

With timely and appropriate treatment, individuals with intermittent exotropia can achieve improved eye alignment and visual comfort. Vision therapy and corrective lenses often yield positive results, especially when initiated early. However, regular follow-up visits with an eye care professional are essential to monitor changes and adjust treatments as needed.

Living with intermittent exotropia can be manageable, especially with proper treatment. Here are some tips to maintain eye health:

1. Regular Eye Check-ups: Routine eye exams can help monitor the condition and detect any changes in alignment or vision.
2. Eye Exercises: Practicing eye exercises can help improve eye coordination over time.
3. Healthy Lifestyle Choices: Maintaining a balanced diet rich in vitamins (especially vitamin A and C) and limiting screen time can contribute to better eye health.
4. Less or no screen time for childeren

Patient compliance

Intermittent exotropia is a manageable condition with the potential for successful treatment, especially if diagnosed early. Parents and individuals experiencing symptoms are encouraged to seek professional eye care to determine the best course of action.

Saleha Zubair

Founder of EyesMatterMost- an optometry student who loves talking about eyes. I tend to cover topics related to optometry, ophthalmology, eye health, eyecare, eye cosmetics and everything in between. This website is a medium to educate my readers everything related to eyes.