In A- or V-pattern strabismus, there is a clinically significantdifference in the horizontal deviation as the eyes move from upgaze todowngaze. This pattern can be seen in esotropia or exotropia. When theeyes diverge more than 10 prism diopter from up gaze to downgaze, anA-pattern is present. When the eyes converge more than 15 prism diopterfrom upgaze to downgaze, a V-pattern is present. There are varioustheories to explain the etiology of the A-V patterns. The oblique muscledysfunction is the most popular theory. An overaction of inferior oblique(in V-pattern) or superior oblique (in A-pattern) is the most commonfinding in cases of A and V pattern strabismus. Other causes of A-Vpatterns include:horizontal recti muscle dysfunction, vertical recti muscle dysfunction andanomalies of muscle insertions or their pulleys. According to thevariability of the etiological theories, surgeries are directed to the musclesbelieved to be implicated. If the pattern is related to overaction of theoblique muscles, these muscles should be weakened. When A-or Vpatternstrabismus occurs in the absence of oblique muscle overaction,the appropriate recession and resection of the horizontal recti is done withappropriate vertical transposition of the tendon. Other procedures are:horizontal transposition of vertical recti and slanting muscle insertion.