To compare associated lower lid retraction (LLR) with control fellow eyelid in patients with unilateral myogenic (MP) and aponeurotic (AP) ptosis before and after the ptosis repair and analyze factors affecting them.

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, lower lid margin reflex distance (MRD2), and photography were performed before and at least 6 months after ptosis repair. MRD2 of >0.5mm from the control eyelid was considered as LLR. 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. Mean MRD2 was 5.5 mm in MP (5 on the non-ptotic side) and 5.6 in AP (4.8 on the non-ptotic side) (P=NS). LLR was observed in 56.9% (33/58) of MP and 80% (16/20) of AP (P=0.06). Preoperative MRD2 was significantly (P=0.01) and negatively (r=-0.3) correlated with MRD1. Mean MRD2 was significantly (P=0.001) decreased from 5.5 to 5 in the MP and 5.6 to 4.9 mm in the AP group. All MP (33/33) and 80% (15/16) of AP group showed ≥0.5 mm improvement in MRD2 at last follow up (P=NS). No variable was significantly associated with mean post-operative MRD2 as well as its success.

LLR are commonly associated with both MP and AP in which the more severe the ptosis the higher the LLR. LLR was improved in all MP and majority of AP, postoperatively.