Clinical Features of Excyclotorsion In The Non-Paretic Eye of Patients With Congenital Unilateral Superior Oblique Palsy

<jats:title>Abstract</jats:title> <jats:p>To investigate preoperative clinical features and postoperative results according to the correspondence between excyclotorsion and the paretic eye in patients with congenital unilateral superior oblique palsy (USOP). A retrospective review of medical charts was performed. The patients were divided into the accordance (preoperative fundus ocular excyclotorsion in the paretic eye) and discordance (preoperative ocular excyclotorsion in the non-paretic eye) groups. The degree of excyclotorsion (scale, 0–4) was measured. Age, sex, hypertropia at the primary position, fixation preference, inferior oblique overaction, and degree of excyclotorsion were measured at each visit. Ninety-eight patients were included in this study. There were 70 (71.4%) and 28 patients (28.6%) in the accordance and discordance groups, respectively. The mean age in the accordance and discordance groups was 9.2 ± 12.7 and 7.5 ± 8.9 years, respectively. Sixteen patients (22.9%) in the accordance group and 12 patients (42.9%) in the discordance group were aged under 2 years (p=0.04). A fixation preference for the paretic eye was observed in two (2.9%) and eight (28.6%) patients in the accordance and discordance groups, respectively (p < 0.01). The accordance group (2.3 ± 0.67) demonstrated a significantly higher degree of excyclotorsion than the discordance group (1.9 ± 0.64) (p = 0.03). The postoperative degree of excyclotorsion in the accordance group (0.14 ± 0.39) was lower than that in the discordance group (0.28 ± 0.71) (p = 0.01). The prevalence of residual postoperative excyclotorsion (>1) in the discordance group was significantly higher (14 patients, 50%) than that in the accordance group (16 patients, 22.9%) (p = 0.01).Twenty-eight percent of the patients with congenital USOP demonstrated excyclotorsion in the non-paretic eye. Preoperative discordance between excyclotorsion and the paretic eye was observed in patients who were under 2 years of age and preferred fixation of the paretic eye. The postoperative degree of excyclotorsion was significantly lower in the accordance group.</jats:p>