The method of dosage anterior transposition of inferior oblique muscle (IOM) in vertical strabismus surgery

Purpose. To study a dosing possibility and to evaluate anefficacy of dosage anterior IOM transposition surgery in case of its overaction of various manifestation degrees and to improve the outcome of vertical strabismus surgery.

Material and methods. An IOM overaction of various manifestation degrees was diagnosed in 82 children. In 22 cases the process was unilateral, in 60 children (120 eyes) — bilateral. The surgery of dosage anterior IOM transposition was performed in 142 eyes. The authors surgically moved the point of original scleral fixation IO to anterior segment of eyeball that is why IOM was transformed from elevator to depressor. The degree of muscle overaction was calculated and result indicated the new exact point to the IOM fixation.

Results. As a result of the dosage intervention in IOM in primary position of gaze vertical deviation was disappeared in 93%. The V-syndrome was eliminated in 82 children. The tilt-head position was corrected in 95,7% of patients with ophthalmic torticollis. Binocular vision was achieved in 98% cases.

Сonclusion. The calculation of a new point of IOM fixation to the eyeball allows to dose predictably the weaking intervention on the inferior oblique muscle in case of its overactions of various manifestation degrees.

Key words: vertical deviation, overaction of inferior oblique muscle, anterior transposition.