The purposes of this study were to compare lash ptosis (LP) with con- tralateral eyelid in patients with unilateral myogenic (MP) and aponeurotic (AP) ptosis before and after the ptosis repair and to assess the correlation between post- operative eyelid height and LP symmetry.

Patients older than 5 years were included from June 2015 to April 2017. Eyelid examination, LP grading (0–3), and photography were performed before and at least 6 months after ptosis repair. Success of ptosis repair (levator resection) was defined as margin reflex distance 1 within 0.5 mm of the contra- lateral eyelid; LP improvement, as at least 1 grade improvement at the last follow-up; and LP symmetry, as 2 eyelids being within 1 grade.

There were 58 patients with MP and 20 with AP, with mean age of 19.2 and 49.5 years and median follow-up of 10 months. Lash ptosis was observed in 89.5% of ptotic and 33.3% of control eyelids. Mean LP grade was significantly higher in the MP (1.5) than in the AP (1.1), which significantly improved to 0.6 and 0.4, respectively. However, it persisted in 50.9% of MP and 31.2% of AP postoperatively. Lash ptosis symmetry was observed in 97.4% of patients, which was not correlated with margin reflex distance 1 symmetry. Lower levator function was the only significant factor correlated with LP.

Lash ptosis was significantly worse in MP than in AP. Lower LF was correlated with more severe LP. Ptosis repair resulted in significant improve- ment of LP and its symmetry with the contralateral eyelid. Lash ptosis symmetry did not correlate with eyelid height symmetry postoperatively.