Self-Grading Effect of Inferior Oblique Recession

Abstract

Inferior oblique (IO) myectomy can result in self-adjustment; the greater the preoperative hyperdeviation, the larger the postoperative correction. This study estimated the effect of IO recession in primary position and in contralateral gaze. Records of 43 patients with IO muscle overaction associated with congenital unilateral superior oblique palsy were reviewed retrospectively. Seventeen patients who had a unilateral 10-mm recession (IO attached at 2 mm temporal and 3 mm posterior from the inferior rectus muscle insertion) and 26 patients who had a standard 14-mm recession were evaluated at 3 months postoperatively. The effect of the recession was measured by preoperative hyperdeviation minus postoperative hyperdeviation. The average preoperative hyperdeviation was 13.4 ± 4.83 prism diopters (PD) in primary position and 16.2 ± 6.32 PD in contralateral gaze in the 10-mm group and 8.0 ± 3.48 PD in primary position and 12.76 ± 4.55 PD in contralateral gaze in the 14-mm group. The average deviation at 3 months postoperatively was 2.1 ± 3.03 in primary position and 2.6 ± 3.95 PD in contralateral gaze in the 10-mm group and 0.8 ± 1.21 in primary position and 1.8 ± 1.95 PD in contralateral gaze in the 14-mm group. The range of self-adjusting effect at 3 months postoperatively was 3 to 20 PD in primary position and 5 to 30 PD in contralateral gaze in the 10-mm group and 3 to 15 PD in primary position and 4 to 24 PD in contralateral gaze in the 14-mm group. The self-grading effect was large and displayed no significant differences at 3 months postoperatively in the 10- and 14-mm groups (P = .104 and .560, respectively). Both IO recession procedures were largely self-grading and no significant differences were evident at 3 months postoperatively.