Lower Eyelid Position Changes Following Müller's Muscle-Conjunctival Resection Blepharoptosis Surgery.

Background: Asymmetry of the lower eyelids and a lower position of the lower eyelid on the ptotic side are common issues in patients with upper lid ptosis. Understanding the relationship between upper lid ptosis correction and lower eyelid position will facilitate better treatment strategies for ptosis.

Objectives: The aim of this study was to assess the lower eyelid position before and after Müller's muscle-conjunctival resection (MMCR) in unilateral myogenic ptosis (MP) and aponeurotic ptosis (AP).

Methods: This prospective interventional before-and-after study included adults with blepharoptosis. Measurements were taken before and 6 months after the surgery.

Results: A total of 47 patients were included, with 29 having MP and 18 having AP. The mean [standard deviation] ages were 31.55 [5.30] years and 50.11 [6.45] years, respectively. In the MP group, there was a significant association between baseline margin reflex distance 2 (MRD2) and the severity of ptosis (MRD1) (β = -0.739, P = .004, multivariate regression analysis). After MMCR, significant decreases were observed in MRD2 for both the MP (-0.38 [0.48] mm, P < .001) and AP (-0.39 [0.47] mm, P = .003) groups. The symmetry of MRD2 remained stable at 41.4% in the MP group, while it decreased from 44.4% to 16.7% in the AP group. The baseline MRD2 was the only factor associated with postoperative MRD2 in the MP group.

Conclusions: Patients with MP and AP often exhibit a lower position of the lower eyelid, which typically elevates after posterior upper lid ptosis surgery. In myogenic cases, the severity of preoperative lower eyelid position correlates with the severity of upper lid ptosis and predicts postoperative elevation of the lower lid.

Level of evidence: 3: