HORIZONTAL TRANSPOSITION OF VERTICAL RECTUS MUSCLES FOR TREATMENT OF EXCYCLOTROPIA

Background: Horizontal transposition of the vertical rectus muscles ha s been performed for treatment of excyclotropia associated with congen ital absence of the superior oblique, and for residual excyclotropia a fter the Harada-Ito operation. However, the amount of excyclotropia th at can be corrected and whether this technique alters the vertical mus cle balance is not well known. We report the surgical results of three patients with pure excyclotropia who underwent unilateral one-half te ndon width horizontal transpositions of vertical rectus muscles. Metho ds: A one-half muscle width temporal transposition of the superior rec tus and nasal transposition of the inferior rectus muscles of one eye was performed in three patients with pure excyclotropia and no associa ted hypertropia. All three had intermittent torsional diplopia before surgery. Results: Postoperatively, excyclotropia decreased significant ly in all fields of gaze, with 8 degrees of reduction by synoptophore and 12.3 degrees of reduction by fundus photography on average, There was no associated vertical or horizontal deviation. All three patients reported improvements of cyclofusion. Conclusion: One-half muscle wid th temporal transposition of the superior rectus and nasal transpositi on of the inferior rectus muscles was effective in ameliorating excycl otropia and corrected subjective complaints without altering vertical muscle balance.