Manchester iStent study: 3-year results and cost analysis

PurposeTo evaluate the safety, efficacy, and the cost of combined phacoemulsification and single iStent insertion in open angle glaucoma (OAG) at 3-years follow-up.MethodsThis was a prospective, uncontrolled, interventional case series. All subjects underwent single iStent implantation combined with cataract surgery by a single surgeon and were followed up over 3 years. Primary outcome measures were the reduction in intraocular pressure (IOP) and number of glaucoma drops at 1, 2, and 3 years. The costs of the procedure vs the cost of continuation of glaucoma drops were calculated and compared in patients who completed 3-years follow-up.ResultsForty-one patients were included in the study and thirty-six patients completed 3-years follow-up. Mean pre-op IOP was 21.2 mm Hg on 2.1 medications. Mean IOP was reduced to 15.9 mm Hg on 0.5 drops, 16.1 mm Hg on 1.0 drops, and 17.1 mm Hg (P<0.001) on 1.3 drops (P<0.001) at 1, 2, and 3 years, respectively. The overall cost of combined cataract surgery and iStent was estimated to be £829.32 more in total than conservative management with brand name eye drops over 3 years (£7.70 per patient per year) and £14 176.9 more if generic drops were used. (£131.3 per patient per year).ConclusionsCombined phaco-iStent proved to be a safe and effective way of managing patients with OAG over our 3-year follow-up period. The cost-effectiveness of the procedure may vary depending on whether brand name or generic eye drops are used.