Table 3. Summary of major randomised clinical trials involves long-term outcomes of GDIs.

Clinical trial	No. of patients	Treatment groups	Follow-up	Major findings
Tube vs Trabeculectomy (TVT) study[21]	212	350-mm2 Baerveldt glaucoma implant, augmented trabeculectomy with mitomycin C	5y	Baerveldt implant had a lower cumulative probability of failure (29.8% Baerveldt vs 46.9% trabeculectomy) Similar mean IOP (14.4 mm Hg Baerveldt vs 12.6 mm Hg trabeculectomy) and mean number of antiglaucoma medications (1.4 Baerveldt vs 1.2 trabeculectomy) between both surgical procedures Trabeculectomy had a higher rate of reoperation (9% Baerveldt vs 29% trabeculectomy)
Primary Tube vs Trabeculectomy (PTVT) study[29]	276	350-mm2 Baerveldt glaucoma implant, augmented trabeculectomy with mitomycin C	1y	Trabeculectomy had a lower cumulative probability of failure (7.9% trabeculectomy vs 17.3% Baerveldt) Similar mean IOP (12.4 mm Hg trabeculectomy vs 13.8 mm Hg Baerveldt) but lower mean number of antiglaucoma medications in trabeculectomy group (0.9 trabeculectomy vs 2.1 Baerveldt) Serious complications requiring reoperation or loss of 2 or more Snellen line greater in trabeculectomy group (7% vs 1%)
Ahmed Baerveldt Comparison (ABC) study[25],[27]		Ahmed glaucoma implant valve FP7, 350-mm2 Baerveldt glaucoma implant	5y	Mean IOP was lower with Baerveldt implant (12.7 mm Hg Baerveldt vs 14.7 mm Hg Ahmed) Use of antiglaucoma medication was similar between implants (1.8 Baerveldt vs 2.2 Ahmed) No significant difference in cumulative probability of failure between implants (39.4% Baerveldt vs 44.7% Ahmed) Baerveldt implant had a greater number of failures due to hypotony, explantation or loss of light perception (17% Baerveldt vs 8% Ahmed)
Ahmed vs Baerveldt (AVB) study[28]	238	Ahmed glaucoma implant valve FP7, 350-mm2 Baerveldt glaucoma implant	5y	Mean IOP was lower with Baerveldt implant (13.6 mm Hg Baerveldt vs 16.6 mm Hg Ahmed) Use of antiglaucoma medication was lower with the Baerveldt implant (1.2 Baerveldt vs 1.8 Ahmed) Baerveldt implant has a lower cumulative probability of failure (40% Baerveldt vs 53% Ahmed) No significant difference in late complications between the implants (69% Baerveldt vs 63% Ahmed) Hypotony resulting in failure was higher in the Baerveldt implant (4% Baerveldt vs 0 Ahmed)

GDI: Glaucoma drainage implant.