Intermittent exotropia is a form of strabismus, or eye misalignment, where one eye occasionally drifts outward. This common condition, particularly in children, arises when the brain’s control over eye alignment falters, especially when a person is tired, ill, or looking at distant objects. While options like glasses or patching may be used, surgery to adjust the eye muscles is a frequent method for correcting the alignment and improving the eyes’ ability to work together.
Determining the Need for Surgery
An ophthalmologist’s recommendation for surgery is based on how the intermittent exotropia impacts vision and daily life. A primary factor is the frequency and duration of the eye turn; if the eye drifts outward for more than 50% of waking hours, it signals a deterioration in the brain’s control. This loss of control indicates that intervention may be necessary to preserve binocular vision, the ability of the eyes to work together to perceive depth.
Doctors also assess how well a patient can straighten their eye, sometimes using tools like the Newcastle Control Score to quantify control. Symptoms leading to a surgical decision include persistent double vision (diplopia), which occurs when the brain can no longer fuse the images from both eyes. Other factors include eye strain, headaches, and the psychosocial impact of the condition, such as a child feeling self-conscious.
Before recommending surgery, non-surgical options are considered. Prescription glasses can correct refractive errors like nearsightedness that may contribute to poor fusion, and patching therapy can be used to encourage the use of the deviating eye. When these methods prove insufficient and stereoacuity (depth perception) worsens, surgery becomes the recommended course of action.
The Surgical Procedure Explained
The goal of intermittent exotropia surgery is to rebalance the extraocular muscles that control eye movement. By adjusting the tension of these muscles, a surgeon can realign the eye. The procedure is performed on an outpatient basis, meaning no overnight hospital stay is required, and is done under general anesthesia, particularly for children.
During the operation, the surgeon makes a small incision in the conjunctiva, the clear membrane covering the white part of the eye, to access the underlying eye muscles. Contrary to a common misconception, the eyeball is not removed or cut open. The surgeon works exclusively on the muscles attached to the outside of the eyeball, and the surgery is often completed in under an hour.
To achieve alignment, the surgeon uses one of two primary techniques: recession or resection. A recession involves detaching a muscle that pulls too strongly and reattaching it further back on the eyeball to weaken its pulling effect. A resection strengthens a muscle by detaching it, removing a small section to shorten it, and then reattaching it in its original position. A combination of these techniques, a recess-resect procedure, is often performed.
The Recovery Process
The initial recovery period involves managing common side effects. Patients will wake from anesthesia feeling groggy, and sometimes a temporary patch is placed over the operated eye. The eye will appear red and swollen, and this can persist for several weeks. A gritty or sandy sensation in the eye is also normal for the first few days.
A crucial part of recovery is adhering to a schedule of eye drops. These typically include an antibiotic to prevent infection and a steroid to reduce inflammation and scarring. Mild pain is expected and can be managed with over-the-counter pain relievers.
Activity restrictions are put in place to protect the healing eye. For the first couple of weeks, patients are advised to avoid activities like swimming or visiting sandboxes to prevent infection or irritation. Rough contact sports should also be avoided. Most children can return to school within a few days, and adults can resume work, depending on their job. Follow-up appointments are scheduled to monitor healing and check the new eye alignment.
Surgical Outcomes and Potential Complications
The most common issues following the procedure are undercorrection or overcorrection. Undercorrection means the eye still has a tendency to drift outward, while overcorrection, known as consecutive esotropia, is when the eye turns inward. Surgeons may aim for a slight initial overcorrection, as the eyes have a natural tendency to drift outward again as they heal.
Temporary double vision is a frequent occurrence after surgery as the brain adapts to the new positioning of the eyes. Before the procedure, the brain may have been suppressing the image from the deviating eye to avoid double vision. Once the eyes are aligned, it takes time for the brain to learn to fuse the two images again, but this symptom usually resolves within a few weeks.
While the surgery is safe, rare complications can include infection, scarring on the surface of the eye, or changes in the position of the eyelid. Prescribed post-operative care, especially the use of antibiotic eye drops, is designed to minimize these risks. Patients should contact their doctor if they experience severe pain, excessive discharge, or a sudden change in vision.
Long-Term Management and Outlook
For many individuals, the alignment achieved through surgery remains stable for many years, providing a long-lasting functional and cosmetic correction that improves binocular vision and self-confidence. Regular monitoring through routine eye exams is important to ensure the alignment remains stable.
Intermittent exotropia can recur over time. The tendency for the eye to drift outward can gradually return, particularly in children as they grow, and some patients may experience recurrence within five to ten years. Should a significant drift return, a second surgery may be recommended. The long-term outlook is positive, but management can be an ongoing process rather than a one-time fix.