Postoperative Levator Function Change in Patients with Unilateral Myogenic versus Aponeurotic Blepharoptosis

Purpose: To compare the change in levator function (LF) after levator resection in patients with unilateral myogenic (MP) and aponeurotic ptosis (AP). Methods: In a prospective study, patients of > 5 years old were included from June 2015 to April 2017. Other types of ptosis, associated strabismus and previous eyelid surgery were excluded. Eyelid examination and photography were performed before and at least 6 months after surgery. Success was defined as Margin reflex distance 1 (MRD1) of within 0.5 mm of the non-ptotic side. All procedures (levator resection) were performed by or under supervision of one oculo-facial plastic surgeon. Results: There were 58 patients in the MP (mean age: 19.2 years) and 20 in the AP (mean age: 49.5) group with median follow up of 10 months. LF was significantly improved from 5.8 to 7.3 mm in the MP and from 11.8 to 13.6 mm in the AP group. LF improvement was not observed in 17.2% of MP and 25% AP group (P=0.5). Mean preoperative LF was significantly (Odd ratio=1.8) higher in patients with than without LF improvement in the MP group. It was significantly reverse in the AP group (Odd ratio=0.38). A significantly positive (r=0.30) and negative (r=-0.72) correlations were observed between preoperative LF and LF improvement in the MP and AP groups, respectively. Success was observed in 90% of AP and 84.5% of MP group. In order of frequency, undercorrection, overcorrection, and contour abnormality were the reasons for failure. No variable significantly affected the success rate in either group. Conclusion: Majority of MP and AP showed postoperative LF improvement. While higher preoperative LF was significantly associated with LF improvement in the MP, it was reverse in the AP group. Success rates were almost the same in both groups with no factor significantly affecting them.