Incidence of Postoperative Ptosis Following Trabeculectomy With Mitomycin C

PURPOSE: To prospectively investigate the incidence of postoperative ptosis following trabeculectomy by comparing preoperative and postoperative margin reflex distance (MRD), and to analyze the clinical factors associated with ptosis. PATIENTS AND METHODS: Patients who underwent trabeculectomy with mitomycin C in unilateral eye between 2010 and 2012 were enrolled. MRD was measured before and 3 and 6 months after trabeculectomy. The MRD is the distance between the light reflex at central cornea and the upper eyelid margin when the patient gazed at a pen light placed 50 cm away straightly. Postoperative ptosis was defined as a decrease in MRD≥2 mm from preoperative level. The correlation among ΔMRD (difference between preoperative and 6 mo postoperative MRD) and clinical factors comprising age, spherical equivalent, preoperative MRD, 6-month postoperative intraocular pressure (IOP), and IOP reduction (difference between preoperative and 6 mo postoperative IOP) was analyzed. RESULTS: Thirty-six patients (36 eyes) were analyzed. Preoperative median MRD was not different between the operated eye and nonoperated fellow eye (both 4.0 mm, P=0.65). The 3- and 6-month postoperative MRD in the operated eye were significantly reduced compared with preoperative MRD (3.0 mm, P=0.04 and 2.5 mm, P=0.01, respectively). The 3- and 6-month postoperative MRD in the nonoperated eye were not different from preoperative MRD (4.0 mm, P=0.81 and 4.0 mm, P=0.85, respectively). The incidence of ptosis at 6 months after operation was 19% (7 of 36 eyes). The IOP was significantly decreased at 3 and 6 months after operation (both P<0.01). No correlation was observed between ΔMRD and all the factors analyzed. CONCLUSIONS: Ptosis is a major complication following trabeculectomy with mitomycin C, with an incidence of 19% at 6 months after operation.