To compare associated lash ptosis (LP) with control fellow eyelid in patients with unilateral myogenic (MP) and aponeurotic (AP) ptosis before and after the ptosis repair and analyze factors affecting it.

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, LP grading (0-3), and photography were performed before and at least 6 months after ptosis repair. LP success was defined as ≥1 grade improvement at the last follow up. All procedures (levator resection) were performed by or under supervision of one oculo-facial plastic surgeon.

Seventy-eight cases with MP (58) and AP (20) with mean age of 19.2 (MP) and 49.5 (AP) years and median follow up of 10 months were included. LP was observed in 69 (89.5%) ptotic and 26 (33.3%) control lids. Mean LP grade was higher in the MP (1.5) than AP (1.1) group (P=0.04) which was significantly (P=0.001) decreased to 0.6 in the MP and 0.4 in the AP group (P=0. 14). LP success was observed in 83% of MP and 82.5% of AP (P=0.83). However, LP was still detected in 50.9% of MP and 31.2% of AP, postoperatively (P=0.16). While more severe LP was preoperatively observed in patients with Lower LF (P= 0.001) and more severe ptosis (P= 0.06), no factor was significantly correlated with post-operative remained LP and LP success.

LP is commonly associated with both MP and AP. Lower LF and more severe ptosis were associated with more severe LP in the MP. Ptosis repair results in significant improvement of LP, even though over half of MP and almost one third of AP groups remained with some degrees of LP, post-operatively.