Performances of glaucoma operations with Kahook Dual Blade or iStent combined with phacoemulsification in Japanese open angle glaucoma patients

AIM:To compare surgical outcomes of phacoemulsification combined with glaucoma surgical techniques performed with either Kahook Dual Blade(KDB)or iStent for Japanese patients with either primary open angle glaucoma or exfoliation glaucoma.METHODS:We retrospectively evaluated the surgical outcomes of 129 eyes of 84 Japanese patients with glaucoma who underwent KDB or 44 eyes of 34 patients who underwent phacoemulsification with iStent procedures combined with cataract surgery.The primary outcome was surgical success or failure[with surgical failure being indicated by<20%reduction from preoperative intraocular pressure(IOP)or IOP>18 mm Hg as criterion A;IOP>14 mm Hg as criterion B on two consecutive study visits;or reoperation requirement].In addition,we assessed the number of postoperative glaucoma medications and the resulting complications.RESULTS:The probability of success was significantly higher in the KDB group than in the iStent group for criterion A(60.2%vs 46.4%,P=0.019).In the KDB group,the mean preoperative IOP of 19.8±7.3 mm Hg decreased significantly to 13.0±3.1 mm Hg(P<0.01),and the mean number of glaucoma medications at 2.5±1.4 decreased significantly to 1.6±1.6(P<0.01)12 mo postoperatively.In the iStent group,the mean preoperative IOP of 17.8±2.9 mm Hg significantly decreased to 14.3±2.3 mm Hg(P<0.01),and the mean number of glaucoma medications at 2.2±1.1 decreased significantly to 0.9±1.4(P<0.01)12 mo postoperatively.The overall IOP reduction percentage was higher in the KDB group(26.2%)than in the iStent group(19.0%)12 mo postoperatively(P=0.03).Hyphema occurred significantly more frequently in the KDB group(16.3%)than in the iStent group(2.3%,P=0.017).CONCLUSION:KDB and iStent procedures combined with cataract surgery both result in significant IOP and glaucoma medication reductions after the 12-month followup.The patients in the KDB group have a higher success rate for the target IOP of less than 18 mm Hg and a higher complication rate than those in the iStent group.