What is the treatment for alternating exotropia in patients of any age, considering their medical history and potential need for surgical intervention?

Treatment of Alternating Exotropia

For alternating exotropia with good fusional control, observation without surgery is recommended, while constant or poorly controlled deviations require surgical intervention, with both bilateral lateral rectus recession and unilateral recess-resect procedures showing equivalent outcomes. 1

Initial Management Approach

Observation vs. Treatment Decision

• Young children with intermittent alternating exotropia and good fusional control should be monitored without surgery, as deterioration to constant exotropia or reduced stereopsis occurs at a low rate 1
• Deviations present most or all of the time require treatment 1
• Surgery is indicated when there is progression to constant or nearly constant deviation, reduced stereopsis, and/or negative effects on social interactions 1

Non-Surgical Management

Refractive Error Correction (First-Line)

• Prescribe corrective lenses for any clinically significant refractive error causing reduced vision 1
• Correct even mild myopia, as improved retinal image clarity often improves exotropia control 1
• Avoid correcting mild-to-moderate hyperopia, as reducing accommodative convergence can worsen the exodeviation 1
• If hyperopic correction is necessary, prescribe the minimum amount needed to maintain good vision while preserving accommodative convergence 1

Stimulating Accommodative Convergence

• If fusional control remains suboptimal despite refractive correction, consider increasing myopic correction in myopes, reducing hyperopic correction in hyperopes, or prescribing myopic correction in emmetropes 1
• Caveat: Older patients and adults may not tolerate this due to visual discomfort or decreased acuity 1
• In children age 3-10, overcorrecting minus-lens therapy may be effective temporarily but is often not maintained and is associated with myopic shift 1

Part-Time Patching

• Part-time patching (2-6 hours daily) may improve fusional control and/or reduce the angle of strabismus, particularly in the 3-10 year age group 1
• Can be done on the preferred eye or, without fixation preference, alternated between eyes 1
• Two randomized clinical trials showed that deterioration is uncommon with or without patching, and patching may slightly lower the probability of deterioration 1

Convergence Exercises

• Orthoptic therapy may improve fusional control in children or adults with convergence insufficiency and small-to-moderate angle exodeviations (≤20 prism diopters) 1
• Near point of convergence exercises on accommodative targets are useful if the near point of convergence is distant 1
• Convergence exercises with base-out prism may be beneficial once near point of convergence improves 1

Amblyopia Treatment

• Though amblyopia is uncommon in intermittent exotropia, if present it should be treated 1
• Treatment may improve fusional control, decrease the angle of exodeviation, and improve postoperative success rates 1

Surgical Management

Indications for Surgery

• Constant exodeviation 1
• Deviation occurring so frequently or so large as to be unacceptable to the child or parent/caregiver 1
• Symptoms not relieved by corrective lenses and nonsurgical treatment 1

Preoperative Considerations

• Measure exotropia with best optical correction using accommodative targets at near, distance, and remote distance 1
• Perform 30 minutes of monocular occlusion (patch test) to elicit the full deviation 1
• If distance angle exceeds near angle by ≥10 prism diopters, place -2.00 D lenses over usual correction to assess for high AC/A ratio 1
• High AC/A ratio patients may warrant nonsurgical approach due to risk of consecutive esotropia with diplopia at near 1

Surgical Procedures

Both bilateral lateral rectus recession and unilateral recess-resect are equally effective initial procedures 1

• A large clinical trial of 197 children age 3-11 with basic-type intermittent exotropia showed no significant difference between bilateral lateral rectus recession and unilateral recess-resect at 6 months and 3 years postoperatively 1
• Reoperation rates by 3 years: 10% for bilateral recession vs. 5% for unilateral recess-resect 1
• When poor vision is present in one eye, unilateral surgery on that eye is typically preferred 1
• Bilateral surgery is preferable with A or V patterns with or without significant oblique overaction 1

Surgical Outcomes and Complications

• Approximately 80% of patients have good alignment at 6 months postoperatively after bilateral lateral rectus recession 1
• Long-term results are less favorable and recurrence is common over time 1
• Consecutive esotropia immediately following surgery often causes diplopia and may be temporary 1
• When consecutive esotropia persists for several weeks, temporary membrane prisms slowly reduced in power can be helpful 1
• Adjustable suture technique has not been shown to improve outcomes in uncomplicated intermittent exotropia 1

Botulinum Toxin

• Insufficient evidence to recommend botulinum toxin treatment for exotropia 1
• In one randomized study, botulinum toxin was less successful than surgery (29% vs. 77%) 1

Follow-Up Protocol

• Children with good fusional control of intermittent exotropia without amblyopia should be examined every 6-12 months 1
• Young children with constant or poorly controlled exotropia or postoperative consecutive esotropia require more frequent follow-up due to amblyopia risk 1
• By age 7-10 years, frequency of examinations may be reduced 1
• Monitor magnitude and frequency of deviation, visual acuity, binocularity, and adherence to treatment plan 1