Is there a functional benefit to surgery on one or two extraocular (eye) muscles for a patient with poorly controlled intermittent exotropia and diplopia, who has not responded to 10 months of patching treatment?

Surgical Management of Poorly Controlled Intermittent Exotropia with Diplopia

Surgery on extraocular eye muscles is strongly indicated for a patient with poorly controlled intermittent exotropia and diplopia who has failed patching treatment, as it provides significant functional benefit by alleviating diplopia and improving binocular vision. 1

Indications for Surgical Intervention

Surgical intervention is clearly indicated in this case based on several factors:

• Poorly controlled intermittent exotropia for 2 years
• Presence of diplopia (double vision)
• Failed conservative treatment (10 months of patching with no improvement)

According to the American Academy of Ophthalmology guidelines, surgery is recommended when:

• The exodeviation is constant or occurs frequently
• The deviation is large enough to be unacceptable
• Symptoms (like diplopia) are not relieved by non-surgical treatments 1

Expected Functional Benefits of Surgery

1. Resolution of diplopia - Primary functional benefit is elimination of double vision, which significantly impacts quality of life 1, 2
2. Improved binocular alignment - Approximately 80% of patients have good alignment 6 months postoperatively 1
3. Restoration of binocular vision and stereopsis - Surgery can help restore depth perception 1
4. Reduction of asthenopia (eye strain) - Particularly important for reading and near work 2

Surgical Options

Two main surgical approaches are recommended:

1. Bilateral lateral rectus muscle recessions - Preferred when distance deviation exceeds near deviation
2. Unilateral surgery (lateral rectus muscle recession and medial rectus resection) - Often used when near deviation is greater than distance deviation 1

A large clinical trial of 197 children showed no significant difference in outcomes between these two approaches at 6 months and 3 years after surgery, with similar rates of suboptimal outcomes 1.

Potential Complications and Management

• Immediate postoperative esotropia - Often temporary and may actually increase likelihood of satisfactory long-term alignment 1
• Persistent overcorrection - More common in older patients and those with greater initial overcorrection 3
• Persistent diplopia - Occurs in approximately 4.3% of patients 3
• Recurrence of exotropia - Moderate risk over time, requiring follow-up 1

If postoperative esotropia persists for several weeks, temporary membrane prisms can be used and gradually reduced in power 1.

Follow-up Protocol

Regular follow-up evaluations are essential to:

• Monitor the magnitude and frequency of any residual deviation
• Assess visual acuity and binocularity
• Check for development of amblyopia (especially in young children) 1

Important Considerations

• While long-term results show recurrence is common over time, the functional benefits of eliminating diplopia and improving binocular vision outweigh this risk 1
• No child in studied cases lost stereoacuity or developed amblyopia due to surgical overcorrection 3
• For patients with persistent diplopia post-surgery, specialized partial occlusion techniques like "spot patching" can be considered instead of full patching to preserve some binocular function 4

The evidence strongly supports proceeding with extraocular muscle surgery in this case of poorly controlled intermittent exotropia with diplopia that has failed conservative management, as it offers significant functional benefits for quality of life and visual function.