Müller muscle-conjunctival resection in modern ptosis surgery: patient selection, technical refinements, and expanding indications.

Müller muscle-conjunctival resection (MMCR) has traditionally been regarded as a posterior approach for mild-to-moderate blepharoptosis in patients with good levator function and a positive response to phenylephrine. Its contemporary role, however, is considerably broader. Accumulating evidence supports the use of MMCR in selected patients with limited or absent phenylephrine responsiveness, more severe ptosis, postoperative eyelid asymmetry, and carefully chosen congenital, neurogenic, or neuromuscular forms of ptosis. In parallel, modifications that incorporate tarsectomy, simplified suturing, conjunctiva-sparing approaches, perioperative bandage contact lenses, and targeted hemostatic maneuvers have sought to improve predictability, comfort, and safety. Important uncertainties nevertheless remain. The mechanism by which MMCR elevates the eyelid is not fully explained by smooth-muscle excision alone; the predictive value of phenylephrine testing is inconsistent; and no single resection algorithm has proved universally reliable. Moreover, surgical success is still reported using heterogeneous definitions that may underrepresent eyelid contour, bilateral symmetry, ocular-surface health, and patient-reported benefit. This review examines the anatomical basis, patient-selection principles, operative algorithms, technical refinements, comparative outcomes, perioperative management, complications, and expanding indications of MMCR. Particular attention is given to the clinical settings in which posterior ptosis surgery may offer practical advantages over external levator advancement and to the limits of the available evidence. Modern MMCR is best understood not as a single formula-driven operation, but as an adaptable posterior lamellar platform whose results depend on individualized planning, meticulous execution, and assessment extending beyond eyelid height alone.