Surgical Treatment of Specific Patterns
Table 10-1 summarizes the surgical treatment of pattern strabismus (see also Chapter 14).
For V-pattern esotropia or exotropia associated with OEAd, weakening of the inferior oblique muscles is performed. For patients who also have dissociated vertical deviation (DVD; see Chapter 11), anterior transposition of the inferior oblique muscle may improve both the V pattern and the DVD. Because patients with V-pattern infantile esotropia who are younger than 2 years are at risk of developing DVD, anterior transposition of the inferior oblique may be considered preemptively for this group.
Table 10-1 Surgical Treatment of Pattern Strabismus
For patients with V-pattern esotropia or exotropia not associated with OEAd, appropriate vertical transposition of the horizontal rectus muscles is performed (see Fig 10-4).
For A-pattern exotropia or esotropia associated with ODAd, weakening of the superior oblique muscles is performed. Tenotomy of the posterior 7/8 of the insertions is an effective method for treating up to 20Δ of A pattern, without a significant effect on torsion. Lengthening of the oblique tendon by recession, insertion of a spacer, or a split-tendon lengthening procedure may also be used to weaken the superior oblique muscles. Bilateral superior oblique tenotomy is a very powerful procedure that may correct up to 40Δ–50Δ of A pattern. There is a risk of induced torsion with this procedure, which may be symptomatic for patients with binocular fusion.
For patients with A-pattern exotropia or esotropia not associated with ODAd, appropriate vertical transposition of the horizontal rectus muscles is performed (see Fig 10-4).
Because Y patterns are not due to overaction of the inferior oblique muscles, weakening these muscles is not an effective treatment. Superior transposition of the lateral rectus muscles can improve this pattern but does not eliminate it.
X patterns are usually due to pseudo-overaction of the oblique muscles, which is caused by contracture of the lateral rectus muscles in large-angle exotropia. Recession of the lateral rectus muscles alone usually improves the pattern.
As stated earlier, these patterns are typically associated with ODAd. Appropriate superior oblique weakening procedures may be used in patients with this pattern.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.