Background <p>Compare the efficacy of combined Hydrus-cataract surgery in open angle glaucoma (OAG) to combined mechanism glaucoma (CMG) and primary angle closure glaucoma (PACG) over 36 months.</p> Methods <p>A retrospective cohort study of patients with CMG, PACG, or OAG who were treated with 1 or more glaucoma medications prior to surgery. Retrospective review of OAG, CMG, or PACG eyes which underwent combined Hydrus-cataract surgery between Jul 2020-Dec 2021. Regression models were used to evaluate IOP, medication use, success rate (IOP ≤ 18 mmHg without medication) and proportion of medication-free eyes.</p> Results <p>The CMG/PACG group (<i>n</i> = 39) had significantly higher IOP reduction from baseline to 36-months than the OAG group (<i>n</i> = 34) (OAG, 15.03 ± 2.90 mmHg to 13.44 ± 3.85 mmHg, <i>p</i> = 0.016; CMG/PACG, 15.62 ± 3.10 to 13.21 ± 2.61 mmHg, <i>p</i> = 0.002) (<i>p</i> = 0.021 for difference). Number of medications was significantly reduced in both groups (OAG, 2.44 ± 1.33 to 1.18 ± 1.40, <i>p</i> &lt; 0.001; CMG/PACG, 2.29 ± 1.27 to 0.87 ± 1.08, <i>p</i> &lt; 0.001) (<i>p</i> = 0.882 for difference). CMG/PACG had higher success rate (49% vs. 29%) and more medication-free eyes (49% vs. 35%) than OAG but these were not statistically significant (<i>p</i> = 0.09 and 0.25, respectively).</p> Conclusions <p>This retrospective study supports the long-term efficacy of combined Hydrus-cataract surgery for CMG/PACG and OAG.</p>