Abstract
Purpose: :
Levator muscle function (LF) is often assessed by measuring eyelid excursion. When reductions in LF are encountered, neuromuscular disease is suspected. Despite the common use and importance of this clinical sign, little attention has been given to normal influence factors. In this study we correlate globe prominence with eyelid excursion.
Methods: :
The study group (n=58, 22 male, 36 female, range 18 to 90 years of age) was identified from patients evaluated during the study period. Inclusion criteria were age >18 and adequate documentation of exophthalmometry measurement results and levator function, bilaterally. Exclusion criteria included any condition affecting globe or eyelid position or eyelid function (other than involutional blepharoptosis). Only right eyes were included in the calculation.
Results: :
An analysis using Pearson's correlation coefficient indicates a statistically significant linear relationship between LF and globe position r(56)=0.54, p<0.001. For these data, the mean (SD) for LF is 17+/-2.7mm and for globe position 15+/-2.2mm. the relationship is defined by the equation y=0.432*x+8.0467 (y=LF and x=exophthalmometry measurement).
Conclusions: :
For every 1mm change in axial globe position a mean change in LF of 0.4mm was observed. This reduction in LF with relative enophthalmos should be considered when interpreting eyelid excursion.
Keywords: eyelid • orbit • eye movements