Exotropia is a type of strabismus where the eyes look away from each other. It is usually intermittent and develops when the patient is several years old. Sensory exotropia is a result of poor vision while essential exotropia is caused by an inability to coordinate the muscles that control the eyes.
Instructions
1. Determine the clinical presentation. The most common initial complaint of a patient with exotropia is eyestrain after a prolonged visual task. The patient also frequently has difficulty maintaining his or her place while reading.
2. Use basic vision tests to assess the patient's control over the exotropia. Some patients may know when the divergence occurs and be able to restore binocular vision voluntarily. Patients that use accommodative convergence to control the exodeviation may complain that objects appear to be closer and smaller than they actually are.
3. Measure the severity of the exotropia. An ophthalmologist will conduct tests to calculate the degree of deviation under a variety of distances and other conditions. These tests will also measure the patient's control over the deviation in addition to lateral and vertical incomitancy.
4. Classify the exotropia. The Duane classification method considers basic exotropia to be a difference of less than 10 prism diopters between near and distance deviation. Divergence excess exotropia is a deviation that increases with distance and convergence insufficiency exotropia occurs when the divergence decreases with distance.
5. Identify the cause of the exotropia. This condition has a genetic component but it can also develop as a result of a significant loss of vision in both eyes. Other sources of exotropia include neurological disorders and abnormalities in the pulley systems of the eye muscles.
Tags: control over, patient control, patient control over, when divergence, with distance