Surgical Outcomes of Bilateral Inferior Rectus Muscle Recession for Restrictive Strabismus Secondary to Thyroid Eye Disease

This retrospective, observational study examined the surgical outcomes of bilateral inferior rectus (IR) recession in thyroid eye disease. Twelve patients who underwent bilateral IR muscle recession were included in the study. Surgical success was defined as patient achievement of the following conditions: (1) a postoperative angle of vertical ocular deviation of <= 3 degrees; (2) a postoperative cyclotropic angle of <= 2 degrees; (3) postoperative binocular single vision, including the primary position; and (4) postoperative enlargement of the field of binocular single vision. Linear regression analyses were performed to analyze the relationship between postoperative changes in the vertical and torsional ocular deviation angles and the amount of IR muscle recession and nasal transposition. Consequently, 9 out of 12 patients were deemed to have had successful surgical outcomes. There was a positive correlation between a change in the vertical deviation angle and a side-related difference in the amount of IR muscle recession in successful cases (crude coefficient, 2.524). A positive correlation was also found between a change in the torsional deviation angle and the amount of IR recession (crude coefficient, 1.059) and nasal transposition (crude coefficient, 5.907). The results will be helpful to more precisely determine the amount of recession and nasal transposition of the IR muscle in patients with thyroid-related bilateral IR myopathy.