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.