The Use of Vertical Offsets with Horizontal Strabismus Surgery

ABSTRACT

Vertical deviation may sometimes coexit with a large horizontal strabismus. If the vertical component is small and comitant, it may be treated by vertical displacement of the horizontal rectus insertions during a monocular recession-resection procedure. A series of 17 patients had vertical displacement of horizontal rectus muscle insertion monocularly combined with recession-resection surgery. Using a surgical plan of 1mm displacement of both medial and lateral rectus insertion to correct each prism diopter of vertical deviation, 12 patients had no residual vertical strabismus. Minimum follow-up period was 3 months. The linear correlation equation between the amount of corrected vertical strabismic angle and that of vertical displacement of medial and lateral rectus muscle is Y=0.67X+0.22(Y=Prism diopter of correction by vertical displacement, X=millimeter of vertical displacement of medial and lateral rectus muscle). These surgical results showed unsatisfactory effect on vertical deviation of more than 6 prism diopters.