Transient descent of the contralateral eyelid in unilateral ptosis surgery

To report novel findings regarding contralateral eyelid height (i.e., intraoperative descent, followed by postoperative elevation) during unilateral ptosis surgery and to comment on their relevance in surgical planning.

Twelve adults with unilateral ptosis underwent levator advancement surgery. During surgery, eyelid height was set to the contralateral preoperative margin reflex distance value, rather than intraoperative level. The margin reflex distance of both eyes was measured before, during, and after surgery.

The mean preoperative margin reflex distance on the ptotic side was 0.63 mm versus 3.83 mm contralaterally. No patient demonstrated a Hering phenomenon preoperatively. In each case, the goal was to elevate the ptotic eyelid to the contralateral preoperative height. For the ptotic eyelid, this resulted in a mean intraoperative margin reflex distance of 4 mm. Simultaneously, the contralateral side was noted to drop in each case, to a mean margin reflex distance of 1.67 mm. Postoperatively, at a mean follow up of 1.25 weeks, the mean margin reflex distance values were 3.88 mm and 3.83 mm for the operated and unoperated sides, respectively (Pearson correlation coefficient = 0.88, p < 0.05). At a mean follow-up of 4.35 months, the mean margin reflex distance values were 3.80 mm and 3.83 mm for the operated and unoperated sides, respectively (Pearson correlation coefficient = 0.96, p < 0.05). No patient had greater than 0.5 mm of asymmetry, and no patient requested postoperative adjustment. Had intraoperative symmetry been obtained with a postoperative contralateral return to preoperative height, a mean 42.1% of postoperative height asymmetry would have resulted between the 2 eyelids.

During unilateral levator advancement surgery, the authors noted that the contralateral eyelid temporarily droops, and this Hering-like effect reverses postoperatively. The authors recommend that by raising the operated eyelid to the height of the contralateral side's preoperative (rather than intraoperative) height, excellent postoperative eyelid height and symmetry can be obtained.