Health Technology Brief

supporting sound, evidence-based decision making

iStent inject Trabecular Micro-Bypass Stent (Glaukos Corp.) in Combination with Cataract Surgery for Management of Open-Angle Glaucoma

June 28, 2019

Health Problem: Glaucoma is a disease of the optic nerve characterized by loss of retinal ganglion cells; remodeling of the lamina cribrosa; structural changes to the nerve; elevated intraocular pressure (IOP); and progressive, irreversible loss of vision leading to blindness. Open-angle glaucoma (OAG) is associated with partial blockage of the flow of aqueous humor.

Technology Description: The iStent inject Trabecular Micro-Bypass System (model G2-M-IS; Glaukos Corp.) is a second-generation iStent device approved for use in conjunction with cataract surgery for the reduction of IOP in adult patients with mild-to-moderate primary OAG (POAG). The iStent inject consists of 2 heparin-coated, titanium, multidirectional stents. The single-piece stent is 230 micrometers (µm) in diameter and 360 µm in height. The iStent inject stent design allows for the rear flange to reside in the anterior chamber and the head to reside in Schlemm’s canal, with the thorax of the stent to be retained by the trabecular meshwork, allowing aqueous humor to drain directly from the anterior chamber of the eye and reducing IOP.

Controversy: Many surgical procedures are associated with pain, infection, hypotony, hemorrhage, corneal edema, and visual disturbances. For these reasons, minimally invasive approaches are sought. However, controversy surrounds the comparative effectiveness of minimally invasive glaucoma surgeries with trabecular bypass stents and whether the long-term effect of such procedures will result in reduced use of glaucoma medications.

Key Questions:

  • Is the iStent inject trabecular micro-bypass stent in combination with cataract surgery effective in managing OAG?
  • How does the iStent inject trabecular micro-bypass stent in combination with cataract surgery compare with clinical alternatives in the management of OAG?
  • Is the iStent inject trabecular micro-bypass stent safe?
  • Have definitive patient selection criteria been identified for the iStent inject trabecular micro-bypass stent?