Predictive value of a phenylephrine-guided resection algorithm in optimizing eyelid symmetry following bilateral...

To evaluate the anatomical, functional, and aesthetic outcomes of phenylephrine-guided bilateral Müller muscle-conjunctival resection (MMCR) using a standardized resection algorithm designed to optimize eyelid symmetry by preoperatively accounting for Hering's phenomenon in patients with mild-to-moderate ptosis METHODS: This retrospective clinical study included patients with good levator function and a positive phenylephrine test who underwent simultaneous bilateral MMCR planned according to a phenylephrine-based resection algorithm. The protocol aimed to simulate postoperative eyelid position and unmask contralateral ptosis related to Hering's law, thereby enabling individualized bilateral surgical planning in a single session. Preoperative and postoperative best-corrected visual acuity (BCVA), margin reflex distance1 (MRD-1) and upper eyelid symmetry were evaluated at postoperative months 1 and 3 RESULTS: A total of 118 eyes from 59 patients (31 females, 28 males) were included. The mean preoperative MRD-1 was 1.24 ± 0.95 mm in the right eye and 1.32 ± 0.84 mm in the left eye. At postoperative month 3, the mean MRD-1 increased to 2.68 ± 0.91 and 2.61 ± 0.78, respectively. Comparison of preoperative and postoperative MRD-1 values demonstrated demonstrated a statistically significant improvement in both eyes at months 1 and 3 (p < 0.001 for each eye). Postoperative MRD-1 outcomes were not significantly different when stratified by the magnitude of the preoperative phenylephrine response (p = 0.32 for right eye, p = 0.06 for left eye). Excellent eyelid symmetry was achieved in 44 patients (74.6%), satisfactory symmetry in 12 (20.3%), and poor symmetry in 3 patients (5.0%). Revision surgery was required in 5 patients (8.4%) during follow-up CONCLUSION: Phenylephrine-guided bilateral MMCR using a standardized resection algorithm is a safe, effective, and highly predictable surgical approach for achieving optimal eyelid symmetry in patients with mild-to-moderate ptosis. Preoperative simulation of postoperative eyelid position by accounting for Hering's phenomenon allows accurate bilateral surgical planning in a single session and may reduce the need for secondary procedures, making this technique a strong first-line alternative to more invasive ptosis repair methods.