PURPOSE: To compare the efficacy of circumferential gonioscopy-assisted transluminal trabeculotomy (GATT) vs hemi-GATT in primary congenital glaucoma (PCG). DESIGN: Prospective randomized controlled trial. METHODS: This study included children with PCG having corneal diameters <
14 mm and relatively clear cornea. The eyes included were randomized to undergo either circumferential GATT (360-GATT) or hemi-GATT (180-GATT). The intraocular pressure (IOP) reduction, requirement for glaucoma medications after surgery, need for repeat surgery, and the incidence and type of complications in each group were analyzed. Surgical success was defined as absolute when IOP ≤18 mm Hg (criterion A) and ≤15 mm Hg (criterion B) was achieved without medications and qualified when the same was achieved with pressure-lowering medications. Eyes with an IOP ≥18 mm Hg on maximum medications, those with IOP <
6 mm Hg, or need for further intervention for IOP control were considered failures. RESULTS: Fifty-two eyes of children with PCG were randomized into either the 360-GATT group (22 eyes) or the 180-GATT group (30 eyes) and followed up for at least 1 year. The median follow-up duration was 22.5 months (range: 12-30 months). IOP fell by 49% and 20.5% with 360-GATT and 180-GATT, respectively, with the final IOP being significantly lower in the former group (P = .0003). For absolute success, the cumulative survival was superior with 360-GATT for both criterion A and B at 1 year (P = .009). Average cup-to-disc ratio, corneal diameter, and axial length reversal were significant in the 360-GATT group but not in the 180-GATT group. CONCLUSIONS: This study reinforces the superior efficacy of circumferential GATT for IOP control in eyes with congenital glaucoma.