Objective: The aim of this study was to compare the outcomes of two-site rigid-probe trabeculotomy (RPT) compared to gonioscopy assisted two-site trabeculotomy (GATT) in the treatment of primary congenital glaucoma (PCG).

Methods: A prospective randomized controlled study SUBJECTS: The study included 77 eyes of 60 PCG patients with clear corneas all aged <5 years. Methods: Patients were randomized to undergo either two-site trabeculotomy using a rigid probe or GATT using a 5/0 polypropylene suture. Success was defined as achieving a final intraocular pressure (IOP) <18 mmHg without (complete) or with medications (qualified). Methods: Primary outcomes were reduction of IOP and medications. Secondary outcomes were complications and success rates. Anterior segment OCT (AS-OCT) was performed to compare changes in angle morphology.

Results: The two-site RPT group included 39 eyes, and the GATT group included 38 eyes. There was a significant reduction in IOP and glaucoma medications at 1, 3, 6, 9 and 12 months postoperatively in both groups (p<0.001) with no significant difference in IOP or glaucoma medications between both groups at any follow-up. At the final follow-up, there was a 49% ± 13% IOP reduction in the two-site RPT trabeculotomy group compared to 44% ± 25% in the GATT group (p=0.2). Success was achieved in all eyes in the RPT group and in 95% in the GATT group. Hyphema was the most frequently observed complication; with no vision-threatening complications in either group. Post-operative AS-OCT findings included angle widening, trabecular shelf, and peripheral anterior synechia.

Conclusions: Circumferential trabeculotomy using ab-interno GATT or ab-externo two-site trabeculotomy yielded comparable results in terms of safety and efficacy. GATT has the advantage of sparing the conjunctiva which may be needed for future interventions.