Full-thickness Eyelid Defect Immediately After Müller Muscle-Conjunctival Resection

Although Müller muscle-conjunctival resection (MMCR) is generally considered safe with a low incidence of complications, the authors report a rare and previously undocumented event: a full-thickness eyelid defect. A 63-year-old male patient with unilateral aponeurotic ptosis underwent MMCR with a 9 mm resection using a Putterman clamp. While the initial postoperative eyelid position was satisfactory, a horizontally 7 mm and vertically 5 mm full-thickness defect was identified following suture removal on postoperative day 10. This defect was not apparent when the patient's eyes were closed or in the primary position, but became noticeable during downgaze. Revision surgery was performed four days later with complete functional and cosmetic recovery. This case highlights the importance of meticulous intraoperative technique and postoperative monitoring, even in minimally invasive procedures like MMCR, to avoid rare but significant complications.