Response to: RE: Long-term outcomes and risk factors for failure with the EX-press glaucoma drainage device

PURPOSE: To report on the long-term outcomes and risk factors for failure with the EX-PRESS shunt implanted under a scleral flap. SETTINGS: Eye Department, University of Ancona, Ancona, Italy and the Oxford Eye Center, University of Witwatersrand, Johannesburg, South Africa. METHODS: The medical records of glaucoma patients who underwent consecutive EX-PRESS implantations under a scleral flap between 2000 and 2009 were reviewed. The operations were performed by two experienced surgeons using an identical surgical technique. The potential risk factors for failure that were analysed included age, sex, race, glaucoma type, previous antiglaucoma medications, previous glaucoma surgeries, diabetes, and smoking. Complete success was defined as postoperative intraocular pressure (IOP) 5 mm Hg>IOP<18 mm Hg without antiglaucoma medications. Qualified success was defined as 5 mm Hg>IOP<18 mm Hg with or without antiglaucoma medications. RESULTS: Two hundred and forty-eight eyes of 211 consecutive patients were included. The mean IOP was reduced from 27.63±8.26 mm Hg preoperatively (n=248) to 13.95±2.70 mm Hg at 5 years (n=95). The mean follow-up was 3.46±1.76 years. Complete and qualified success rates decreased gradually from 83% and 85% at 1 year to 57% and 63% at 5 years follow-up, respectively. The risk factors for failure were diabetes, non-Caucasian race, and previous glaucoma surgery. Complete success rates of diabetic patients and non-Caucasian patients decreased from 63% and 75% at 1 year to 42% and 40% at 5 years follow-up, respectively. CONCLUSIONS: EX-PRESS success rates decrease over time but compare favourably with trabeculectomy literature data. The main identifiable risk factors for failure are diabetes, non-Caucasian race, and previous glaucoma surgery