Twelve-Month Outcomes of iStent Infinite in Severe Open-Angle Glaucoma Compared with iStent Inject W in Mild-to-Moderate Disease

Background/Objectives: The efficacy of two-stent implantation with iStent inject W is well established for mild-to-moderate open-angle glaucoma (OAG), whereas evidence for three-stent implantation with iStent infinite in severe OAG remains limited. We compared 12-month outcomes of a severity-based surgical strategy, using two stents in mild-to-moderate OAG and three stents in severe OAG. Methods: This retrospective study included 100 eyes with OAG that were followed for at least 12 months after trabecular micro-bypass stent implantation. Eyes with mild-to-moderate disease, defined as visual field mean deviation (MD) of −12 dB or better, received two stents (iStent inject W), whereas eyes with severe disease, defined as MD worse than −12 dB, received three stents (iStent infinite). Outcomes included intraocular pressure (IOP), glaucoma medication burden, visual field parameters, corneal endothelial cell density (ECD), surgical success, and additional glaucoma surgery. Results: Baseline IOP and the number of glaucoma medications were higher in the three-stent group. At 12 months, mean IOP was similar between groups. Although the three-stent group showed a greater unadjusted reduction in IOP, this difference was not significant after adjustment for baseline IOP using analysis of covariance. Linear mixed-model analysis also showed no significant group effect or time-by-group interaction. Glaucoma medications decreased significantly in both groups, with a similar mean reduction, although the three-stent group had a greater medication burden at 12 months. Changes in visual field parameters and corneal ECD did not differ significantly between groups. Surgical success and the need for additional glaucoma surgery were also not significantly different between groups. Conclusions: In this retrospective cohort, three-stent implantation in severe OAG was associated with 12-month IOP outcomes similar to those observed in the two-stent group with mild-to-moderate OAG, although this was achieved with a greater residual medication burden. This approach appears feasible for patients with severe OAG.