Revision ptosis surgery for under-correction after Müller muscle conjunctival resection

Introduction: Müller muscle conjunctival resection (MMCR) may be more likely to lead to under- rather than over-correction. The choice of revision surgery is not clearly defined. Methods: MMCR patients were included if the post-operated eyelid(s) demonstrated margin reflex distance-1 (MRD1) less than 3.5 mm, or if MRD1 asymmetry was greater than 0.5 mm, and if they underwent subsequent revision surgery. MRD1 was the primary outcome measure and complications were secondary outcome measures. Two groups were defined: patients who underwent MMCR then repeat MMCR (M-M) and those who underwent MMCR followed by external levator resection (ELR) surgery (M-L). Results: 18 eyelids (16 patients) were included, 12 in M-M and 6 in M-L. Mean (SD) preoperative MRD1 was 1.84 mm (0.97), range -0.41 to 3.39 mm. There was no difference (p = 0.70) in preoperative MRD1 between M-M and M-L. In the M-M group, mean (SD) MRD1 was 1.77 mm (1.12) preoperatively, 2.35 mm (0.66) after the first surgery, and 3.44 mm (0.31) after revision. Mean MRD1 was significantly higher after revision, compared to preoperatively (p < 0.05) and after first surgery (p < 0.05). In the M-L group (n = 6), mean (SD) MRD1 was 1.98 mm (0.90) preoperatively, 1.99 mm (0.56) after the first surgery and 3.44 mm (1.24) after revision. The difference between preoperative and post revision surgery MRD1 was significant (p < 0.05). Conclusions: For patients with insufficient elevation of MRD1 or with asymmetry after MMCR, revision by MMCR or by ELR are both reasonable options.