Purpose: To create a highly balanced comparison of ab interno trabeculectomy (Trabectome, AIT) and trabecular bypass stenting (iStent, TBS).Setting: Eye and Ear Institute, Pittsburgh, Ross Eye Institute, Buffalo, and Glaucoma Associates of Texas, Dallas, USA.Design: Retrospective Exact Matching analysis.Methods: AIT and TBS patients were included from three large glaucoma practices. The primary outcome measure was the unmedicated IOP ≤ 21 mmHg at 2-year follow-up visit. A secondary measure was unmedicated IOP reduction ≥ 20% at 2 years. Patients were matched by baseline IOP, the number of glaucoma medications and glaucoma type using Exact Matching and by age using Nearest Neighbor matching. Patients without a close match were excluded. All surgeries were combined with phacoemulsification. Results: 154 AIT and 110 TBS eyes were analyzed. 48 AIT patients were exactly matched to 48 TBS patients. Both groups had a baseline IOP of 15.3±3.1 mmHg. At 24 months, the mean IOP was 13.9±3.3 for AIT versus 16.8±2.8 mmHg for TBS (p=0.04), while the number of medications was 0.7±1.0 for AIT versus 1.7±1.2 for TBS (p=0.04). The proportion of subjects achieving IOP ≤ 21 mmHg without medications at 24 months was 53% in AIT versus 16.6% in TBS (P < 0.05). At 24-month follow up 17.6% of patients in AIT had ≥ 20% IOP reduction without medication versus no patient in TBS. Conclusions: An Exact Matching comparison of AIT and TBS demonstrated greater IOP reduction with fewer medications in AIT.