Abstract: Objective  To evaluate the clinical efficacy of single-plane anatomical dissection of the levator palpebrae superioris complex combined with conjoint fascial sheath （CFS） suspension in the correction of severe ptosis. Methods  A retrospective analysis was performed on the clinical data of 20 patients（ 22 eyes） with severe congenital ptosis from June 2020 to September 2024. The study included 12 males （14 eyes） and 8 females （8 eyes）， aged 11-35 years， with a mean age of 17.5 years. All patients received single-plane anatomical dissection of the levator palpebrae superioris complex combined with CFS suspension. At 6 months and 1 year after surgery， margin reflex distance 1（ MRD1）， defined as the distance from the midpoint of the upper eyelid margin to the corneal light reflex， was measured to evaluate surgical outcomes. Postoperative complications were also recorded. Results  Postoperatively， 16 eyes were classified as cured， with a cure rate of 72.7%； 4 eyes （18.1%） were improved ； and 2 eyes（ 9.2%） were ineffective . The MRD1 value at 6 months after the operation was（ 3.38±0.36） mm， and the MRD1 value at 1 year after the operation was （2.68±0.54） mm. One patient developed exposure keratitis due to improper postoperative care and recovered after symptomatic treatments. No other serious complications were observed. Conclusion Singleplane anatomical dissection of the levator palpebrae superioris complex combined with CFS suspension for the treatment of severe congenital ptosis has the advantages of less trauma， excellent efficacy and higher safety， and has certain clinical application value.

Key words: Conjoint fascial sheath, &emsp, Ptosis, &emsp, Levator palpebrae superioris