Comparative effectiveness and safety of GATT with or without ABiC in patients with open-angle glaucoma

Background This is the first comprehensive comparison between gonioscopy-assisted transluminal trabeculotomy (GATT) and GATT combined with ab interno canaloplasty (ABiC) in patients with OAG. Purpose The purpose of this study was to compare the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) combined with ab interno canaloplasty (ABiC) with those of GATT alone in patients with open-angle glaucoma (OAG). Design This was a retrospective, comparative case series. Participants Patients with primary open angle glaucoma who underwent GATT (27 eyes in Group 1) or GATT + ABiC (26 eyes in Group 2) were included. Methods Outcomes including intraocular pressure (IOP), glaucoma medications, and surgical complications were analyzed. Main outcome measures Surgical success was defined in terms of IOP and medication use as follows: (1) a preoperative IOP > 21 mmHg and a postoperative IOP ≤ 21 mmHg with at least a 20% reduction from baseline with (qualified success) or without (complete success) glaucoma medications or (2) a preoperative IOP < 21 mmHg while taking 3 or more glaucoma medications and a postoperative IOP ≤ 21 mmHg with a reduction of more than two medications (qualified success) or with no medications (complete success). Results At 12 months, the mean IOP was 14.8 ± 2.2 mmHg in Group 1 and 16.6 ± 2.3 mmHg in Group 2 ( p = 0.008). The number of medications was 0.6 ± 1.0 in Group 1 and 0.9 ± 1.3 in Group 2 ( p = 0.334). At 24 months, the mean IOP was 15.3 ± 2.0 mmHg in Group 1 and 15.5 ± 2.4 mmHg in Group 2 ( p = 0.676). The number of medications was 0.5 ± 0.9 in Group 1 and 0.9 ± 1.1 in Group 2 ( p = 0.197). The complete success rates were 63.0% in Group 1 and 50.0% in Group 2 ( p = 0.16), and the qualified success rates were 81.5% in Group 1 and 76.9% in Group 2 ( p = 0.51). Conclusion The GATT procedure, with or without ABiC, is safe and effective in decreasing the IOP and the number of antiglaucoma medications used.