Recurrence of Hypertropia in Sagging Eye Syndrome

OBJECTIVE: This study aimed characterized evolution of surgical outcomes treating hypertropia in sagging eye syndrome (SES). DESIGN: Retrospective interventional case series at a single center. PARTICIPANTS: Patients (mean age 71 years) undergoing strabismus surgery for hypertropia caused by SES, having at least 1 month of postoperative follow-up. METHODS: Time-to-event analysis estimated cumulative recurrence and overcorrection. Multivariable logistic regression evaluated predictors. MAIN OUTCOME MEASURES: Hypertropia recurrence, motor alignment success at follow-up, degree of hypertropia correction, and incidence of recurrence and overcorrection. RESULTS: In 128 patients (62 self-reported males), strabismus surgery immediately reduced average hypertropia in distant, central gaze from 4.0 ± 2.8Δ preoperatively to 0.6 ± 2.8Δ postoperatively (P < .001). Despite initial correction, at final follow-up 769 ± 867 (standard deviation) days after surgery, 39 (31%) patients exhibited symptomatic hypertropia. This included 32 patients (25%) who had recurrence of original hypertropia, and 7 (6%) due to overcorrection. Recurrences accrued gradually over time without an early plateau, and had no significant demographic or clinical associations. After adjustment for preoperative hypertropia, graded vertical rectus tenotomy and vertical rectus muscle recession exhibited similar recurrence risk (P = .110), while magnitude of preoperative hypertropia itself was not associated with overcorrection (odds ratio 1.15, P = .264). CONCLUSIONS: Strabismus surgery effectively corrects hypertropia caused by SES, yet after about 2 years, roughly a quarter of patients develop delayed recurrent hypertropia, consistent with the progressive degenerative pathophysiology of SES. Surgical overcorrections are uncommon and may be overestimated due to progressive SES changes in the fellow eye.