Angle‐based minimally invasive glaucoma surgery in normal tension glaucoma: A systematic review and meta‐analysis

Abstract Background This systematic review and meta‐analysis quantitatively examines the efficacy of angle‐based minimally invasive glaucoma surgery (MIGS) in normal tension glaucoma (NTG). Methods A literature search was performed on Medline, Embase, PubMed, CINAHL and Cochrane Library from inception until 20 December 2022. Pilot, cohort, observational studies and randomised controlled trials including at least 5 subjects undergoing angle‐based MIGS (trabecular‐bypass devices, excisional trabeculotomy, goniotomy and ab‐interno canaloplasty) for NTG, with or without cataract surgery, were included. Meta‐analysis of continuous outcome using the meta routine in R version 2022.12.0+353 was performed to determine mean intraocular pressure (IOP) and anti‐glaucoma medication (AGM) reduction post‐operatively. Results Of the 846 studies initially identified, 15 studies with a pooled total of 367 eyes which underwent combined phacoemulsification and angle‐based MIGS were included for final meta‐analysis. Outcomes of the iStent were reported in 5 studies, iStent inject in 7 studies, Hydrus Microstent in 1 study, Kahook Dual Blade in 3 studies, and Trabectome in 2 studies. There was significant reduction in both IOP and AGM post‐operatively at 6 months (2.44 mmHg, 95%CI: 1.83–3.06; 1.21 AGM, 95%CI: 0.99–1.44), 12 months (2.28 mmHg, 95%CI: 1.71–2.84; 1.18 AGM, 95%CI: 0.90–1.47), 24 months (2.10 mmHg, 95%CI: 1.51–2.68; 1.26 AGM, 95%CI: 0.85–1.68) and 36 months (2.43 mmHg, 95%CI: 1.71–3.15, 0.87 AGM, 95%CI: 0.21–1.53) (all p < 0.05). Subgroup analysis on combined phacoemulsification‐iStent inject surgery demonstrated a reduction in both IOP (2.31 mmHg, 95%CI: 1.07–3.56, p < 0.001) and AGM (1.07 AGM, 95%CI: 0.86–1.29, p < 0.001) at 12 months post‐operatively. Conclusions Angle‐based MIGS combined with phacoemulsification effectively reduces IOP and AGM in NTG eyes for up to 36 months after surgery.