The Effect of Vertical Transposition of Horizontal Muscles on Vertical Deviation Associated with Horizontal Strabismus

ABSTRACT

The authors performed vertical transposition of the horizontal rectus muscles during monocular recession-resection surgery to correct the comitant vertical deviation associated with the horizontal strabismus. When the eye was hypertropic, infratransposition of horizontal rectus muscles was performed and when the eye was hypotropic, supratransposition of the insertions of the horizontal muscles was performed. For vertical strabisumus with 4 delta-12 delta(mean 7.7 delta) angle deviation, each medial and lateral rectus muscles were vertically transposed 2mm-4.5mm(mean 3.1mm) in 51 eyes. Fourty four eyes(86.3%) were vertically aligned, 4 eyes(7.8%) were undercorrected, and 3 eyes(5.9%) were overcorrected with 19.1 months of follow-up periods in average. By one millimeter vertical transposition of horizontal recti, vertical deviation was corrected by 1.21 delta in average. The vertical transposition of horizontal recti can be an effective method for correcting vertical deviation associated with horizontal strabismus not associated with any cyclovertical muscle dysfunction.