Superior Oblique Palsy: Characteristics and Treatment Outcomes

Purpose To evaluate the characteristics, prognostic factors, and treatment outcomes in patients with superior oblique (SO) palsy.Methods A retrospective review was conducted on patients diagnosed with SO palsy at King Chulalongkorn Memorial Hospital from January 2012 to October 2022. Patient demographics, etiology, preoperative strabismus evaluations, treatment approaches, and surgical outcomes were analyzed. Motor and sensory success criteria were ocular deviation ≤5 PD vertically, ≤10 PD horizontally, and the resolution of diplopia.Results Among 57 patients, 43 (75.4%) had acquired SO palsy, most commonly due to ischemia (50.9%). Unilateral involvement was observed in 48 patients (84.2%), while 9 (15.8%) had bilateral SO palsy. Congenital cases had higher odds of requiring surgery (OR 30, 95% CI [3.55–253.86]; p < .001) compared to acquired cases that resolved spontaneously. Among 26 surgeries, inferior oblique (IO) myectomy was the most common (57.7%). Motor and sensory successes were achieved in 84.6% and 50% of cases respectively. Vertical deviation improved from 13 (6–20) to 0 (0–3) PD (p < .001) at distance and from 13 (6–20) PD to 0 (0–3) PD (p < .001) at near. Postoperative drift toward overcorrection was noted at both distance (−4 [−5 to −2] PD; p < .001) and near (−4 [−8 to −1] PD; p = .002) but stabilized by 12 months. The Harada-Ito procedure reduced extorsion in bilateral cases from 25 (22–30) to 5 (0–10) degrees (p < .001), correcting 10 (7.5–11) degrees for each operated eye (p = .02).Conclusions SO palsy management requires individualized treatment. Congenital cases were more likely to require surgery. IO myectomy is effective for vertical deviations ≤15 PD, while larger misalignments need combined procedures. The Harada-Ito procedure corrected 10 (7.5–11) degrees of extorsion for each operated eye in bilateral SO palsy. Aiming for early small residual hypertropia is advisable due to postoperative drift to overcorrection, particularly in congenital cases with large fusional amplitudes.