Stereopsis impairment and its association with fovea-disc angle in congenital superior oblique palsy patients with compensatory head posture: a cross-sectional study.

Purpose: To characterize stereopsis impairment in patients with congenital superior oblique palsy (CSOP) with compensatory head posture (CHP) and to explore the fovea-disc angle (FDA) as a potential imaging parameter for assessing binocular visual dysfunction. Methods: This cross-sectional study enrolled 20 CSOP patients with CHP and 20 age- and sex-matched controls between November 2024 and March 2026. Stereopsis was assessed using the Titmus Stereotest, Randot Stereotest (near), and Distance Randot Stereotest under both the CHP and the primary position. Stereopsis was compared between CSOP patients and controls, and between the CHP and the primary position within the CSOP group. Stereopsis was categorized as normal (≤100 arcsec) or impaired (>100 arcsec), and the proportions of CSOP patients with impaired distance and near stereopsis under the CHP were compared. FDA was measured using fundus photography and an imaging analysis software in patients with CSOP. Correlation analyses were performed to evaluate the associations between log-transformed stereopsis and clinical parameters. Results: CSOP patients with CHP showed significantly worse stereopsis than controls (Titmus: Conclusion: CSOP patients with CHP exhibit impairment in both distance and near stereopsis, with distance stereopsis being more severely affected. Binocular FDA is negatively correlated with stereopsis and may serve as a promising imaging parameter for assessing binocular visual dysfunction in CSOP with CHP.