Upper eyelid retraction: meta-analysis & systematic review of surgical outcomes

Background: Upper eyelid retraction (UER) is the hallmark of thyroid eye disease and a recognized complication of aesthetic and reconstructive eyelid surgery. Multiple levator-Müller targeted procedures exist, yet technique selection remains empirical, and no prior quantitative synthesis focused on posterior-lamellar lengthening has been available. Methods: A PRISMA-guided systematic review and single-arm meta-analysis was performed. Studies reporting MRD1 (Marginal Reflex Distance 1) change, anatomical success, or reoperations rates after retractor-lengthening surgery were included. Subgroup and meta-regression analyses assessed baseline severity, surgical macro-area, approach, etiology, and spacer material. Risk of bias was evaluated using ROBINS-I and RoB 2. Results: Thirty-nine studies comprising 2064 patients (3096 eyelids) were analyzed. Pooled ΔMRD1 was 2.71 mm (95% CI 2.36-3.06) and anatomical success 85% (95% CI 80.6-89.1%). Preoperative severity explained most heterogeneity (β = 0.72 mm/mm; p < 0.0001), while surgical technique had no independent effect after adjustment. Reoperation rate was 12% (95% CI 9.1-15.5%), with increased odds after levator-only procedures (OR 3.5; p = 0.014) and levator/Müller recession-resection (OR 2.5; p = 0.034). Autologous spacers provided higher success (88%) and fewer reoperations (5%) than non-autologous grafts (76%; 25%). Overcorrection was more frequent with levator-only techniques (OR 5.6; p = 0.020), whereas undercorrection correlated inversely with baseline severity (β = -0.33; p = 0.045). Conclusions: Surgical correction of UER yields reliable outcomes when matched to disease severity. Baseline retraction, rather than technique, predicts postoperative eyelid position, while reoperation risk differentiates procedures, favoring blepharotomy and autologous spacers. These findings support a severity-matched approach for surgical planning and patient counseling.