Comparison of gonioscopy-assisted transluminal trabeculotomy versus trabeculectomy with mitomycin C in patients with open-angle glaucoma

Precis: Trabeculectomy (TRAB) lowers the intraocular pressure (IOP) more than gonioscopy-assisted transluminal trabeculotomy (GATT) at 18 months, with a reduction in IOP of 30% or more and a significant reduction in the number of glaucoma medications compared with baseline. Purpose: To compare the IOP-lowering efficacy of GATT with mitomycin-C augmented TRAB in patients with uncontrolled open-angle glaucoma. Methods: Single-center, retrospective, comparative cohort study. One hundred ten consecutive patients (110 eyes) underwent GATT (n=61) or TRAB (n=49). The primary outcome measure was IOP reduction, defined as a percentage decrease >= 30% and absolute IOP <= 18 mm Hg at 18 months with (qualified) or without (complete) medications. Secondary outcomes were visual field change, number of glaucoma medications, complications, and reintervention. Results: The mean +/- SD baseline IOP was 30.04 +/- 7.5 and 27.59 +/- 4.70 (P=0.072) with the mean number of medications of 3.08 +/- 0.73 and 2.92 +/- 0.91 (P=0.310) in TRAB and GATT, respectively. At 18 months, the mean +/- SD IOP was 15.26 +/- 3.47 mm Hg and 12.48 +/- 4.58 mm Hg after GATT and TRAB, respectively (P=0.002). The percentage of IOP lowering from baseline was 56.05 +/- 17.72 after TRAB and 42.04 +/- 15.56 after GATT (P<0.001). Percentages of complete and qualified success were 59% and 27% after TRAB and 46% and 31% after GATT (P=0.353). No change in visual field loss was observed in both groups. The mean reduction in medications was 2.3 +/- 1.4 and 2.1 +/- 1.5 in TRAB and GATT, respectively (P=0.493). The most frequent complication after TRAB was hypotony and after GATT hyphema. Reintervention occurred in 8.2% of cases after TRAB and in 14.8% after GATT (P=0.341). Conclusions: IOP lowering was greater after TRAB than after GATT at 18 months with a significant reduction in the number of medications after both procedures. Complications and reintervention occurred equally in both groups but differed in type.