Enhancing uveoscleral outflow
The CyPass Micro-Stent (Alcon Laboratories), approved by the FDA in 2016, and the iStent Supra (Glaukos), which is still investigational, lower IOP by increasing uveoscleral outflow. Discussing this mechanism, Dr. Vold referred to the benefit of prostaglandin analogues.
“Prostaglandin analogues have a substantial IOP-lowering effect,” Dr. Vold explained. “We know they act by increasing uveoscleral outflow. In fact, uveoscleral outflow is considered to be IOP-independent and contributes up to 57% of natural aqueous outflow.”
Dr. Vold pointed out that by tapping into the uveoscleral outflow pathway bypasses Schlemms canal and collector channels, which may be atrophic in glaucoma patients. The hope for these devices is to provide significant IOP lowering with the safety profile similar to cataract surgery alone.
The CyPass Micro-Stent is a supraciliary device that had impressive efficacy in clinical trials, reducing IOP in patients with mild-to-moderate glaucoma by up to 35% while reducing medication use. Recently published results from the U.S. pivotal trial, COMPASS, reported 93% of patients achieved an IOP <18 mm Hg without medications.
“We now have 7.5 years of experience with this device, and the long-term data are also impressive,” Dr. Vold said.
There also is potential to increase the IOP-lowering effect achieved with the CyPass Micro-Stent by delivering viscoelastic to the supraciliary and suprachoroidal spaces to create and maintain a space for enhanced aqueous outflow. If that approach proves effective, this device may be considered in eyes with more moderate or advanced glaucoma, Dr. Vold said.
The platform also may be used as a sustained-release drug delivery system and for treating retinal neovascular disease.