Purpose: To assess the role of muscular degeneration, we evaluated the correlation between ptosis severity and levator muscle function.
Design: Retrospective cohort study.
Methods: The medical records of 136 patients (53 men and 83 women; mean age, 67 years) with acquired blepharoptosis were reviewed for levator function (LF), margin reflex distance (MRD), age, and gender. Multivariate linear regression was performed for statistical analysis.
Results: A significant correlation (P < .001) was seen between MRD (mean, 1.0 + 1.0 mm; range, -3.0 to 3.0 mm) and LF (mean, 15.0 + 1.0 mm; range, 11.0 to 20.0 mm). On average, a 0.5-mm reduction in LF was observed for each 1.0-mm decrease in MRD. This was independent to other variables assessed.
Conclusions: In patients with involutional blepharoptosis, a directly proportional decrease in levator function and eyelid height was observed. This may implicate an abnormality of the levator muscle itself as a contributing factor in the development of involutional blepharoptosis.