Levator Disinsertional Type Ptosis; Muscle Action Better Defined Using 2 Phase Levator Function Assessment

Abstract

Purpose: : To identify differences in levator function in patients with disinsertional type ptosis by using the 2 Phase method of recording levator function.

Methods: : 25 consecutive patients with levator disinsertional type ptosis and 25 normal patients were examined using the standard method of recording levator function and the previously described 2 Phase assessment¹. The latter technique records levator function in 2 phases; Phase 1 measured from downgaze to primary position and Phase 2 from primary position to upgaze.

Results: : The average total lid excursion was similar for each group; normals 15.5mm and disinsertional ptosis 14.9mm.In normal patients the average lid excursion in phase 1 was 10.2mm, and phase 2, 5.3 mm. This represents a ratio of 1:1.92 (phase 2: phase 1). In patients with levator disinsertional type ptosis, the average lid excursion in phase 1 was 7.6mm, and in phase 2, 7.3 mm, representing a ratio of 1:1.04.Expressed as a percentage of total lid excursion a difference between these 2 populations was highlighted. In normals, phase 2 represents 34% of the total lid excursion whilst in the aponeurotic ptosis group, phase 2 represents 49% of the total lid excursion. There is a statistically significant difference in phase 2 between normal patients and those with disinsertional ptosis, with phase 2 representing a greater proportion of the total lid excursion in the ptotic patients.

Conclusions: : An increase in levator function on upgaze in those with disinsertional ptosis has been identified by other authors ², although this is not the case in all forms of ptosis as we have previously reported. As the 2 Phase technique of levator function assessment records the movement of the lid in different positions of gaze we can now confirm this previous observation and better define the nature of upper lid movement both in those patients with normal lid function and in those with ptosis.1. Jones C.A., Lee E.J., Sparrow J.M., Harrad R.A., Levator Function Revisited; A two phase aassessment of lid movement to better identify levator-superior rectus synkinesis. Accepted for publication in Br J Ophth2. Hirasawa C, Matsuo K, Kikuchi N, Osada Y, Shinohara H, Yuzuriha S. Upgaze eyelid position allows differentiation between congenital and aponeurotic blepharoptosis according to the neurophysiology of eyelid retraction. Ann Plast Surg 2006;57:529-534

Keywords: eye movements: recording techniques • eyelid • anatomy