Comparative analysis of clinical features following inferior oblique recession surgery for unilateral congenital superior oblique palsy

Purpose

To assess changes in three clinical features (hypertropia in primary gaze, head tilt, and fundus extorsion) following inferior oblique recessions in patients with unilateral congenital superior oblique palsy (SOP).

Methods

We retrospectively reviewed medical records of patients with unilateral congenital SOP who underwent inferior oblique recession at our center between 2020 and 2023. Patients were excluded if they had amblyopia, hypertropia >20^Δ in primary gaze, bilateral SOP, acquired SOP due to head trauma, neurological causes, or cerebrovascular diseases, or a history of previous strabismus surgery. The pre- and postoperative measurements of hypertropia in primary gaze, head tilt, and fundus extorsion were analyzed, and postoperative improvement was calculated as the percentage reduction from the preoperative value. Correlations between outcomes with regard to the amount of postoperative improvement were analyzed.

Results

A total of 81 patients were included. Mean preoperative hypertropia was 11.6^Δ, head tilt was 15.1°, and fundus extorsion was 11.0°. The postoperative follow-up period was 15.4 months. The average amount of postoperative improvement was 77% for hypertropia, 58% for head tilt, and 75% for fundus extorsion. Improvements in hypertropia and fundus extorsion were significantly correlated (R² = 0.403, P < 0.001); however, improvements in hypertropia and head tilt (R² = 0.0011, P = 0.36) and head tilt and extorsion (R² = 2.190, P = 0.967) were not significantly correlated.

Conclusions

Hypertropia in primary gaze and fundus extorsion improved more than head tilt, and the improvements were significantly correlated.