Comparative evaluation of iStent versus iStent inject W combined with phacoemulsification in open angle glaucoma

Abstract

Purpose The study aimed to compare the 12-month post-operative outcomes of iStent and iStent inject W (inject W), and the factors associated with their success in open-angle glaucoma. Methods This single-center, retrospective comparative case series evaluated the medical records of patients who underwent iStent (comprising 1 stent) or inject W (comprising 2 stents) implantation with cataract surgery for primary open-angle glaucoma and normal tension glaucoma between January 2019 and March 2022. The 12-month post-operative efficacy outcomes included intraocular pressure (IOP), glaucoma medications, and survival analysis of the probability of success. “Failure” was defined as any of the following conditions compared to baseline: 1) IOP elevation, 2) increased glaucoma medication, or 3) IOP decline not exceeding 20% when glaucoma medication scores were comparable, and 4) need for additional glaucoma surgery. The safety outcomes included intra- and post-operative adverse events and changes in the best-corrected visual acuity and visual field. Results The study comprised 55 eyes in the iStent and 105 in the inject W groups. At 12 months, treatment success was achieved in 66.0% of iStent and 78.4% of inject W eyes. The mean IOP was lower, and the percent reduction from baseline was equal in iStent-treated eyes (8.0% reduction, 14.8 mmHg to 13.7 mmHg, P<0.01) and inject W-treated eyes (11.9% reduction, 15.0 mmHg to 13.8 mmHg, P<0.01) (between-group comparison, P = 0.23). The mean medication burden decreased significantly from 2.5 to 1.1 for iStent (55.0% reduction, P<0.01) and 2.9 to 1.7 for iStent inject (46.8% reduction, P<0.01), with no significant differences between the two groups (P = 0.17). Both devices exhibited excellent safety. Conclusions Both devices significantly reduced IOP and glaucoma medication 12 months post-operatively. The outcome measures did not differ significantly between the two groups, and lower baseline IOP was predictive of surgical failure.