Congenital aponeurotic ptosis.

Congenital aponeurotic ptosis is the result of a failure of the distal end of the aponeurosis to attach in the usual position. There is a ptosis of varying degree disproportionate to the amount of levator function. Unlike dystrophic congenital ptosis, the amount of levator function is good, usually exceeding 9 to 10 mm. Corrective surgery was performed in 12 cases of congenital aponeurotic ptosis, including identical twins with unilateral symmetrical ptosis, supporting the concept of a developmental mesodermal anomaly.