Method
- Cadaver dissection: 9 Korean and 5 Caucasian upper eyelids.
- Microscopy with hematoxylin-eosin, Masson trichrome, and elastin stains.
- Dynamic high-resolution MRI of 4 healthy young Korean men.
Findings
- More subcutaneous and suborbicularis fat, including a pretarsal fat component, in Asian eyelids.
- Asian double eyelids had fat amounts between Asian single eyelids and Caucasian eyelids.
- In Asian single eyelids, the orbital septum fuses to the levator aponeurosis below the superior tarsal border; in Caucasian eyelids, fusion is above that border.
- The preaponeurotic fat pad extends anteriorly to the tarsal plate in the Asian single eyelid but not the Caucasian eyelid.
- A pretarsal fat pad was identified only in Asian single eyelids.
What it means for a patient
- This explains the anatomic difference behind the single eyelid (no crease) common in Asian eyelids: lower septal fusion and more fat let the fat pad sit in front of the tarsal plate, blocking crease formation.
- This anatomy is the basis surgeons use for double eyelid surgery, which recreates the crease by managing this fat and septal fusion level.
- This is a cadaver and imaging anatomy study, not a surgical outcomes study.
Citations
PubMed https://pubmed.ncbi.nlm.nih.gov/10408455/.
Terms
- Suborbicularis fat: a fat layer beneath the orbicularis oculi muscle of the eyelid.
- Pretarsal fat pad: a fat pad in front of the tarsal plate, present in some Asian eyelids.
- Levator aponeurosis: the tendon of the muscle that lifts the upper eyelid.