Treatment of Strabismus
Strabismus treatment should focus on restoration of binocularity, control of diplopia, reconstruction of normal-appearing alignment, improved eye contact, and enhanced self-image. 1
Types of Strabismus
Strabismus encompasses various conditions characterized by ocular misalignment:
- Divergence insufficiency: More common in adults over 50, especially Caucasian women, with esotropia greater at distance than near 1
- Sagging eye syndrome: Prevalent in older adults (60% of cases in patients over 90), with esotropia often accompanied by small vertical deviation and cyclotropia 1
- Strabismus fixus (Heavy eye syndrome): Associated with high myopia (axial length >27mm), progressive esotropia and possible hypotropia 1
- Sensory strabismus: Occurs with vision loss in one or both eyes, with exotropia more common (69%) than esotropia (31%) 1
Diagnostic Approach
A thorough examination should include:
- Detailed history of diplopia, vision changes, and previous treatments 1
- Measurement of misalignment using prism and alternate cover test at distance and near 1
- Assessment of versions, ductions, and forced ductions 1
- Evaluation for associated conditions like blepharoptosis or deep superior lid sulcus defect 1
- Imaging (CT, MRI) when necessary to evaluate muscle position, especially in post-traumatic cases 1
Treatment Options
1. Observation/Monitoring
- Appropriate for mild, occasional symptoms that are well-tolerated 1
- May be suitable for post-traumatic strabismus that could improve with time 1
2. Non-surgical Management
- Optical correction: Full correction of refractive error, including appropriate bifocals or progressive lenses 1
- Prism correction: Can be incorporated into glasses for small-angle deviations 1
- Occlusion therapy: Temporary relief of diplopia through patching 1
- Botulinum toxin injection: Can be used alone or as an adjunct to surgery, providing temporary or permanent improvement 1
3. Surgical Management
- Timing: Wait 4-6 months after orbital trauma to ensure stability of misalignment unless there is substantial fat and orbital pulley entrapment requiring earlier repair 1
- Techniques:
- Recession/resection procedures 1
- Adjustable sutures: Particularly helpful in adults for unpredictable cases like restrictive or paralytic strabismus 1
- Tenotomy procedures for small deviations (<8 prism diopters horizontally, <3 prism diopters vertically) 1
- Transposition procedures for lost or severely paretic muscles 1
Outcomes and Success Rates
- Approximately 80% of adult patients achieve satisfactory alignment with one surgical procedure 2
- Most adults experience improvement in binocular function after strabismus surgery, even with longstanding strabismus 2
- Benefits typically include expansion of binocular visual fields, with some patients regaining stereopsis 2
Special Considerations
Anticoagulation Management
- Many strabismus surgeons do not routinely stop anticoagulants 1
- Consultation with the prescribing physician is advised before temporary discontinuation 1
- Absorbable gelatin sponges with or without thrombin may be useful in difficult cases 1
Complications
Common but mild complications include:
More serious complications (rare) include:
- Overcorrection or undercorrection requiring additional surgery 1
- Diplopia (0.8%, more common in adults) 1
- Limitation of eye movements 1
- Slipped muscle (1 in 1,500) or lost muscle (1 in 4,500) 1
- Anterior segment ischemia (1 in 6,000; higher risk with age) 1
Provider Selection
- Treatment requires the training and clinical judgment of an experienced ophthalmologist, preferably a pediatric ophthalmologist or strabismologist 1
- Orthoptists working under ophthalmologist supervision can assist with examination, diagnosis, and non-surgical management 1
- A multidisciplinary approach may be beneficial, particularly in complex cases 1