Primary PreserFlo MicroShunt Versus Trabeculectomy: Effectiveness and Safety in the Real World

Backgrounds/Objectives: Trabeculectomy is the gold standard for glaucoma drainage surgery but is associated with a risk of sight-threatening complications. The PreserFlo MicroShunt (PF) is a less invasive alternative that aims to reduce complications and simplify post-operative care. This study aimed to compare the effectiveness and safety of PF to trabeculectomy in the management of glaucoma. Methods: This was a retrospective cohort analysis of 95 eyes (48 PF, 47 trabeculectomy) from a single-center private practice in Brisbane, Australia. Data were collected from November 2017 to January 2024. Primary outcomes included intraocular pressure (IOP) and number of medications. Secondary outcomes included best-corrected visual acuity (BCVA) and complications. Inverse probability of treatment weighting (IPTW) was applied to baseline covariates, and weighted regression and Cox proportional hazards models were then used to estimate treatment effects. Results: The two groups had comparable patient characteristics, although the PF group was older with worse visual field mean deviation. At 12 months, both procedures significantly reduced IOP and medications; however, differences were not statistically significant between groups (2.9 mmHg; 95%CI: -2.0, 7.9; P=0.303, and 0.4; 95%CI: -0.13, 0.96; P=0.138, respectively). The estimated probabilities of qualified success were comparable (74.9% PF vs 72.5% trabeculectomy). Intra-operative stenting in PF eyes eliminated early post-operative hypotony. The incidence of open surgical revision in the PF group vs. the trabeculectomy group was 14.6% vs. 2.1% (P=0.059, respectively). PF was associated with faster post-operative inflammation resolution (hazard ratio: 6.3; 95%CI: 2.8, 14.5; P<0.001). Conclusions: Both PF and trabeculectomy are effective for glaucoma management. PF is a less invasive procedure with a lower rate of early hypotony when stented. Trabeculectomy has a tendency for lower IOP reduction and less requirement for open revision, although this did not reach statistical significance. This highlights the need for longer term studies and improved techniques such as more effective anti-fibrotic strategies.