Purpose: This study evaluates the effect of unilateral blepharoptosis repair on contralateral eyelid position and assesses the relation between preoperative eyelid height interdependence, consistent with Hering law, and surgical outcome.
Methods: The medical records of 54 patients (21 men, 33 women; mean age, 65 years) who underwent external levator advancement for unilateral aponeurotic blepharoptosis were reviewed for preoperative and postoperative margin reflex distance (MRD) of the nonoperated eye. To assess the relation between preoperative Hering dependence (mechanical elevation of the ptotic eyelid causing a decrease in contralateral eyelid height) and postoperative eyelid position, the change in MRD of the nonoperated eye was compared between subjects who on preoperative evaluation did (n=18) and did not (n=36) demonstrate eyelid height interdependence, using the 2-sample t test.
Results: After unilateral blepharoptosis repair, the mean (+/- SD) change in contralateral MRD was -0.2 +/- 0.8 mm. There was no significant difference in contralateral MRD change in subjects with and without preoperative Hering dependence (-0.3 +/- 0.8 mm versus -0.2 +/- 0.9 mm, respectively, p=0.78). Seventeen percent (9 of 54) of patients had a contralateral MRD decrease of more than 1 mm. Three patients (5.6%) required contralateral blepharoptosis repair within 1 year of initial surgery.
Conclusions: After levator advancement for unilateral blepharoptosis, roughly 17% of patients will have a decrease in contralateral eyelid height of more than 1 mm, with 5% of patients requiring surgical repair during the first postoperative year. The degree of change in contralateral eyelid height cannot be reliably predicted by preoperative assessment of Hering dependence.