Predicting the Success Rate of Levator Resection Surgery Using Whitnall Ligament Position

Ptosis is defined as lower positioning of the upper eyelid margin which normally is placed 1.5 mm below the superior corneal limbus [1]. Ptosis can be accounted as the 3rd most common eyelid disorders following chalazion and entropion [2]. It may result in amblyopia, visual field defect, cosmetic and psychological problems. Generally, ptosis is subdivided to congenital and acquired cases [3]. Abnormal development of levator muscle or innervation abnormalities is responsible for congenital cases of ptosis. On the other side, trauma, several neurologic disease, and defective levator aponeurosis can lead to acquired ptosis [4]. Levator function, clinical feature, and concomitant eyelid or face abnormalities are the determining factors for choosing appropriate surgical plan [5]. Common surgical approaches include frontalis suspension technique and levator muscle procedures (levator advancement and levator resection) in which frontalis suspension is performed in cases with poor levator function and the latter one is suitable for patients with preserved levator function [4]. Levator resection outcomes are not absolutely predictable. Multiple factors such as ptosis severity, levator function, and age of patient have been discussed as predictive factors for surgical success rate.