Gonioscopy-assisted transluminal trabeculotomy, ab interno trabeculotomy: technique report and preliminary results

Purpose: To introduce a minimally invasive, ab interno approach to a circumferential 360-degree trabeculotomy and to report the preliminary results.

Design: Retrospective, noncomparative cases series.

Participants: Eighty-five eyes of 85 consecutive patients who sought treatment at Glaucoma Associates of Texas with uncontrolled open-angle glaucoma and underwent gonioscopy-assisted transluminal trabeculotomy (GATT) for whom there was at least 6 months of follow-up data.

Methods: Retrospective chart review of patients who underwent GATT by 4 of the authors (D.S.G., D.G.G., O.S., R.L.F.) between October 2011 and October 2012. The surgery was performed in adults with various open-angle glaucomas.

Main outcome measures: Intraocular pressure (IOP), glaucoma medications, visual acuity, and intraoperative as well as postoperative complications.

Results: Eighty-five patients with an age range of 24 to 88 years underwent GATT with at least 6 months of follow-up. In 57 patients with primary open-angle glaucoma, the IOP decreased by 7.7 mmHg (standard deviation [SD], 6.2 mm Hg; 30.0% [SD, 22.7%]) with an average decrease in glaucoma medications of 0.9 (SD, 1.3) at 6 months. In this group, the IOP decreased by 11.1 mmHg (SD, 6.1 mmHg; 39.8% [SD, 16.0%]) with 1.1 fewer glaucoma medications at 12 months. In the secondary glaucoma group of 28 patients, IOP decreased by 17.2 mmHg (SD, 10.8 mmHg; 52.7% [SD, 15.8%]) with an average of 2.2 fewer glaucoma medications at 6 months. In this group, the IOP decreased by 19.9 mmHg (SD, 10.2 mmHg; 56.8% [SD, 17.4%]) with an average of 1.9 fewer medications (SD, 2.1) at 12 months. Treatment was considered to have failed in 9% (8/85) of patients because of the need for further glaucoma surgery. The cumulative proportion of failure at 1 year ranged from 0.1 to 0.32, depending on the group. Lens status or concurrent cataract surgery did not have a statistically significant effect on IOP in eyes that underwent GATT at either 6 or 12 months (P > 0.35). The most common complication was transient hyphema, seen in 30% of patients at the 1-week visit.

Conclusions: The preliminary results and safety profile for GATT, a minimally invasive circumferential trabeculotomy, are promising and at least equivalent to previously published results for ab externo trabeculotomy.