Müller Muscle Conjunctival Resection: A Prospective Multicenter Comparison of Eyelid Height at the Immediate, 1-Week, and 3-Month Postoperative Time Points.

PURPOSE: The primary objective was to document change in postoperative marginal reflex distance-1 (MRD1) after Müller muscle conjunctival resection surgery. The secondary objective was to identify predictors of change in postoperative MRD1. METHODS: A multicenter prospective cohort study was performed on patients consecutively recruited for Müller muscle conjunctival resection. MRD1 was measured immediately after Müller muscle conjunctival resection, at the 1-week postoperative visit, and the ≥3-month postoperative visit. MRD1 at the immediate and 1-week time points were compared with MRD1 ≥3 months using descriptive statistics. Predictors of change in MRD1 were analyzed using multivariate regression analysis. RESULTS: A total of 150 patients (226 eyelids) were included. Regarding the immediate to ≥3-month interval, 53.8% of eyelids remained clinically similar (rise or fall ≤0.5 mm), 19.8% rose ≥1 mm, and 26.4% fell ≥1 mm. Regarding the 1-week to ≥3-month interval, 76.5% remained clinically similar, 17.3% rose ≥1 mm, and 6.2% fell ≥1 mm. No variable predicted change in MRD1 over either interval with both clinical and statistical significance. CONCLUSIONS: Immediate postoperative MRD1 is likely to reflect the late result in only 54% of cases. However, 1-week postoperative MRD1 is similar to the late result in 77% of cases and is highly unlikely (6%) to fall by the final visit. No variable significantly impacts change in postoperative MRD1.

Prevalence and Predictors of Hering's Response in Müller's Muscle-conjunctival Resection.

PURPOSE: Determine the prevalence and predictors of Hering's response following Muller's muscle-conjunctival resection (MMCR). METHODS: Seventy-five consecutive patients undergoing unilateral MMCR were recruited in this prospective, multicenter, cohort study. Margin-reflex distance-1 (MRD1) of both eyelids was recorded preoperatively and postoperatively. One hundred forty-three variables were investigated as potential predictors of a late postoperative (≥3 months) Hering's response using regression analyses. Main outcome measures were Hering's response (≥0.5 mm descent of the unoperated eyelid from baseline), and a clinically relevant Hering's response (descent of the unoperated from baseline to a MRD1 ≤ 2.0 mm, or descent from baseline such that the MRD1 of the unoperated eyelid became >1 mm lower than the operated eyelid). RESULTS: Twenty-four (32.0%) patients had a late postoperative Hering's response, but only 6 (8.0%) responses were clinically relevant. A Hering's response at the immediate (OR 16.24, p = 0.02) and 1-week postoperative (OR 8.94, p = 0.04) timepoints predicted a late postoperative response. However, the presence (OR 7.84, p = 0.07) and amplitude (OR 8.13, p = 0.06) of a preoperative phenylephrine Hering's response did not predict a late postoperative response. Of the 10 patients with a clinically relevant phenylephrine Hering's response, only 1 demonstrated a clinically relevant response late postoperatively. CONCLUSION: Unilateral MMCR induces a clinically relevant Hering's response in 8% of patients. A preoperative phenylephrine Hering's response does not predict a late postoperative Hering's response. Therefore, when unilateral phenylephrine testing unmasks contralateral blepharoptosis, only the side with blepharoptosis at baseline should be operated.