Strabismus pp 97-114 | Cite as

A-Pattern, V-Pattern, and Other Alphabet Pattern Strabismus

  • Burton J. Kushner


The terms A-pattern and V-pattern describe horizontal strabismus that is vertically incomitant and has a substantial difference in the horizontal deviation between the midline upgaze and midline downgaze positions. A patient with a V-pattern is more esotropic or less exotropic in downgaze than upgaze and an A-pattern is characterized by the converse. By convention, the difference between upgaze and downgaze must be 15 prism diopters (∆) or greater to diagnose a clinically significant V-pattern and 10 ∆ to diagnose an A-pattern. Less commonly, there are variations of pattern strabismus in which there is minimal change from downgaze to the primary position, but the eyes diverge in upgaze, resulting in a Y-pattern. Converse to a Y-pattern, the main exo shift may be between the primary position and downgaze to form a “λ” (lambda) pattern. Divergence in both upgaze and downgaze constitutes an X-pattern.


A-pattern Alphabet patterns: Etiology, Insertion slanting, Pseudo inferior oblique overaction, Pulley abnormalities, Role of torsion, Transpositions for, Treatment Insertion slanting Pseudo inferior oblique overaction V-pattern X-Pattern Y-pattern 


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© Springer International Publishing AG 2017

Authors and Affiliations

  • Burton J. Kushner
    • 1
  1. 1.Department of Ophthalmology and Visual SciencesUniversity of Wisconsin-MadisonMadisonUSA

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