Abstract
Twenty to 50 % of patients with horizontal strabismus have ocular deviations that measure significantly more or less in upgaze than in downgaze and have been designated as having A- or V-pattern strabismus. An A-pattern strabismus exists when the magnitude of deviation is more convergent or less divergent in upgaze. Conversely, a V-pattern strabismus exists when the magnitude of deviation is less convergent or more divergent in upgaze. Causes of A- and V-pattern strabismus have been attributed to superior or inferior oblique muscle overaction, horizontal rectus muscle overaction or underaction, increases or decreases in vertical rectus muscle adduction, or anatomic abnormalities in the orbit or of the tendon pulley system of the eye muscles. If an A- or V-pattern is clinically significant (greater than 10 prism diopters for A-pattern deviation between upgaze and downgaze measurements or greater than 15 prism diopters for V-pattern deviation), surgical treatment directed at alleviating the pattern is undertaken in combination with treatment of the horizontal deviation. The most common treatment options include weakening of the oblique muscles when overactive, and vertical displacement, or transposition, of the horizontal rectus muscles.
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Straight, S.M., Bahl, R.S. (2016). A- and V-Pattern Strabismus. In: Traboulsi, E., Utz, V. (eds) Practical Management of Pediatric Ocular Disorders and Strabismus. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-2745-6_54
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DOI: https://doi.org/10.1007/978-1-4939-2745-6_54
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