Gonioscopy-Assisted Transluminal Trabeculotomy Following Failed iStent Surgery

We describe 4 cases of eyes initially treated with phacoemulsification and iStent trabecular microbypass (Glaukos Corporation). These patients subsequently required further surgery and were successfully treated with the removal of the iStent device followed by gonioscopy-assisted transluminal trabeculotomy (GATT), using the iTrack catheter (Ellex Medical Lasers Ltd). Three of the cases had prior first-generation iStent (G1), and 1 had prior second-generation iStent (G2). This case series demonstrates that in selected cases, a further angle procedure in the form of a GATT can show efficacy and durability in the medium term. Our patients had controlled intraocular pressures (IOPs) at 1-year post-GATT: 2 on IOP-lowering therapy and 2 without any IOP-lowering medications. Three patients had transient hyphema and 2 with high IOP in the immediate postoperative period. No patients experienced a decrease in best-corrected visual acuity postoperatively. To the best of our knowledge, there is no prior literature describing this surgical strategy. This series demonstrates that GATT could potentially be an effective procedure in the case of a failed initial iStent microtrabecular bypass.