RESUMEN
Exact understanding of the upper eyelids is essential to the success of an anterior surgical approach for the correction of blepharoptosis. Therfore, we undertook this study using cadaver dissection, histologic sections, surgical observations, and review of MRI findings to gain a better understanding of the anatomical characteristics of the orbital septum and associated connective tissue structures which are important in ptosis surgery. The basic distinction of the upper eyelid structures between Oriental and Occidental is the relationship of the orbital septum and the levator aponeurosis. The orbital septum appears as a thick multilayered connective tissue originating just inside the superior orbital rim, but its inferior extension become thin progressively and blends with levator aponeurosis on an average of 1.6mm below the superior tarsal horder. Therefore the preaponeurotic fat is allowed to proceed to the anterior tarsal surface, resulting in a characteristic appearance of oriental eyelids. The levator aponeurosis maintains its thick and obvious structure continuously to the anterior tarsal surface near the lower margin of the upper lid. We resected levator aponeurosis with Muller's muscle which plays a important role in lid elevation for the correction of congenital htepharoptosis, and obtained excellent results.