Hering’s response in ptosis surgery
Reviewed by James Hsuan

his is a prospective study of the Hering’s response in patients undergoing Muller’s muscle-conjunctival resection (MMCR) ptosis surgery, with a particular reference to the accuracy of preoperative phenylephrine testing. Patients with unilateral ptosis were assessed clinically preoperatively, in the immediate postoperative period, one week postoperatively and over three months postoperatively, including a phenylephrine test in the ptotic eye during the preoperative assessment. Those who responded with at least 1mm elevation or correction of the ptosis after 2.5% phenylephrine was administered, underwent a MMCR ptosis repair. A positive Hering’s response was defined as a descent of the contralateral upper lid of 0.5mm or more, and a clinically relevant response as descent of the unoperated lid to a margin reflex distance 1 (MRD1) of 2mm or less, or 1mm lower than the operated lid. The authors found that at the late (over three months postoperative) assessment 24 (32%) patients had a Hering’s response in the unoperated eye, but only six (8%) were clinically relevant. Although a Hering’s response noted at the immediate and one-week postoperative assessments predicted a late (over three months) Hering’s response, the preoperative phenylephrine test could not predict it. Ten patients had a positive Hering’s response to the phenylephrine test, but only one of these had a clinically significant late response. The authors conclude the preoperative phenylephrine test is an inaccurate predictor of a late Hering’s response, and therefore advise against simultaneous bilateral surgery based on the phenylephrine test, but rather recommend reassessment of the fellow eye following surgery. They state the results cannot be correlated to anterior approach ptosis surgery.

Prevalence and predictors of Hering’s response in Müller’s muscle-conjunctival resection.
Lussier C, Leung VC, El-Khazen Dupuis J, et al.
OPHTHALMIC PLASTIC AND RECONSTRUCTIVE SURGERY
2023;39:237-42.