iStent

The iStent ® Trabecular micro-bypass stent was approved by the FDA for use in conjunction with cataract surgery for the reduction of intraocular pressure in adult patients with mild-moderate open-angle glaucoma in July 2012. The iStent is intended to create a bypass through the trabecular meshwork to Schlemm’s canal to improve aqueous outflow through the natural physiologic pathway.{P080030B.pdf (fda.gov)}

The iStent inject Trabecular micro-bypass system was approved by the FDA in June 2018 for the same indication as the iStent, and contains contains two preloaded titanium intraocular stents{P170043B.pdf (fda.gov)}

Implantation of two istent inject stents in subjects with OAG resulted in IOP and medication reduction and favorable safety outcomes at 12 months.{Voskanyan L, García-Feijoó J, Belda JI, Fea A, Jünemann A, Baudouin C; Synergy Study Group. Prospective, unmasked evaluation of the iStent® inject system for open-angle glaucoma: synergy trial. Adv Ther. 2014 Feb;31(2):189-201.}

There was a greater reduction in IOP without medication after iStent inject implantation with cataract surgery versus cataract surgery alone at 2 years, with excellent safety.{Samuelson TW, Sarkisian SR Jr, Lubeck DM, Stiles MC, Duh YJ, Romo EA, Giamporcaro JE, Hornbeak DM, Katz LJ; iStent inject Study Group. Prospective, Randomized, Controlled Pivotal Trial of an Ab Interno Implanted Trabecular Micro-Bypass in Primary Open-Angle Glaucoma and Cataract: Two-Year Results. Ophthalmology. 2019 Jun;126(6):811-821.}

Patients with combined single istent and cataract surgery had significantly better IOP control on no medication through 24 months than patients having cataract surgery alone, with similar favorable long-term safety profile.{Craven ER, Katz LJ, Wells JM, Giamporcaro JE; iStent Study Group. Cataract surgery with trabecular micro-bypass stent implantation in patients with mild-to-moderate open-angle glaucoma and cataract: two-year follow-up. J Cataract Refract Surg. 2012 Aug;38(8):1339-45.}

Patients who underwent istent plus cataract surgery had significantly better IOP reduction on fewer medications versus cataract surgery alone at 12 months, with similar overall safety profile.{Samuelson TW, Katz LJ, Wells JM, Duh YJ, Giamporcaro JE; US iStent Study Group. Randomized evaluation of the trabecular micro-bypass stent with phacoemulsification in patients with glaucoma and cataract. Ophthalmology. 2011 Mar;118(3):459-67.}

Based on data synthesized in Cochrane reviews, randomized clinical trial data associate the Hydrus with greater drop-free glaucoma control and IOP lowering than the iStent; however, these effect sizes were small.{Bicket AK, Le JT, Azuara-Blanco A, Gazzard G, Wormald R, Bunce C, Hu K, Jayaram H, King A, Otárola F, Nikita E, Shah A, Stead R, Tóth M, Li T. Minimally Invasive Glaucoma Surgical Techniques for Open-Angle Glaucoma: An Overview of Cochrane Systematic Reviews and Network Meta-analysis. JAMA Ophthalmol. 2021 Sep 1;139(9):983-989.}

The Hydrus had a greater rate of complete surgical success and reduced medication use compared to 2 istent at 1 year{Ahmed IIK, Fea A, Au L, Ang RE, Harasymowycz P, Jampel HD, Samuelson TW, Chang DF, Rhee DJ. A Prospective Randomized Trial Comparing Hydrus and iStent Microinvasive Glaucoma Surgery Implants for Standalone Treatment of Open-Angle Glaucoma: The COMPARE Study. Ophthalmology. 2020 Jan;127(1):52-61.}