Outcomes and Complications of Minimally Invasive Glaucoma Surgeries (MIGS) in Primary Angle Closure and Primary Angle Closure Glaucoma: A Systematic Review and Meta-Analysis.

Topic: To analyse the safety and efficacy of minimally invasive glaucoma surgeries (MIGS) in lowering IOP and medication burden in primary angle closure (PAC) or primary angle closure glaucoma (PACG).

Clinical relevance: MIGS is off-label in angle closure, as implantation of the device is difficult when there is iridotrabecular contact. However, access to the trabecular meshwork may be established with cataract removal or goniosynechiolysis. While MIGS can be performed in the same setting as phacoemulsification (MIGS-phaco), it remains controversial if the combined procedure confers a significant advantage over standalone phacoemulsification.

Methods: We performed a systematic search of MEDLINE, EMBASE, and Cochrane library for studies reporting outcomes of MIGS in PAC or PACG. Our main outcome measures were IOP-lowering from baseline and medication reduction, at 1 year. We performed meta-analyses of these outcomes using weighted mean differences (WMD) under random-effects models. Our secondary outcome was complication rate.

Results: Twenty-three studies comprising 875 patients were included in our review, from which 15 (590 patients) were included in meta-analysis. MIGS (with and without phacoemulsification) demonstrated a weighted mean reduction in IOP of 7.71 mmHg (95% CI: 5.16-10.26), and in medication of 1.57 (95% CI: 1.17-1.96), both at 1 year. Subgroup analyses revealed the superiority of AIT over endoCPG and iStent in both IOP-lowering (p<0.02) and medication burden (p<0.01). Comparison analysis between MIGS-phaco vs standalone phacoemulsification revealed superiority of MIGS-phaco in reducing medication burden (WMD 0.59, 95% CI: -0.04-1.22) and to a limited extent, IOP-lowering (WMD 1.22; 95% CI: -0.96-3.39) up till 1 year. Overall complication rate was 141/875 (16%) after excluding transient self-resolving hyphema.

Conclusion: MIGS brings about sustained reduction in IOP and medication burden with favourable side-effect profile in angle closure eyes. MIGS-phaco may be superior to standalone phacoemulsification. MIGS should be thoroughly considered for mild-moderate PACG with coexisting cataract before pursuing more invasive surgical approaches.