The levator palpebrae superioris muscle transitions from its muscular belly at the level of Whitnall ligament to a broad, thin aponeurosis that fans out to insert on the anterior face of the upper eyelid tarsal plate, the skin of the upper eyelid crease, and the orbital septum. The aponeurosis is approximately 14-20 mm wide at its tarsal insertion and has medial and lateral horns attaching to the orbital walls and the lacrimal gland.
The levator aponeurosis is the surgical target in ptosis repair: aponeurotic ptosis from disinsertion or stretching of the aponeurosis from the tarsus is the most common adult ptosis type, corrected by external levator advancement. In severe congenital ptosis with poor levator function, frontalis suspension using a silicone rod or fascia lata graft bypasses the aponeurosis entirely. Over-advancement produces eyelid retraction; under-advancement leaves residual ptosis. The aponeurotic crease position determines the upper eyelid crease height in blepharoplasty and ptosis surgery.
Disinsertion or stretching of the levator aponeurosis from the tarsus, occurring with age, after cataract surgery from speculum pressure, in contact lens wearers, or after eyelid swelling, produces a high skin crease with good levator function and variable ptosis, corrected by levator aponeurosis advancement suture or resection through an eyelid crease incision.
Excessive advancement of the levator aponeurosis during ptosis repair produces upper eyelid retraction and lagophthalmos with corneal exposure, requiring early revision by releasing or recessing the over-advanced aponeurosis.
