Clinical Investigation of New Glaucoma Procedures

Kateki Vinod; Steven J. Gedde


Curr Opin Ophthalmol. 2017;28(2):187-193. 

In This Article

Targeting the Suprachoroidal Space

The uveoscleral pathway provides an alternate route for natural aqueous outflow, promoted by a negative pressure gradient between the suprachoroidal space and anterior chamber. Data have been published for only one of the new gonioscopy-assisted surgeries targeting the suprachoroidal space.

CyPass Micro-stent

The supraciliary microstent (CyPass Micro-Stent; Transcend Medical, Inc., Menlo Park, California, USA) is a 6.35 mm fenestrated polyimide device that is inserted between the scleral spur and ciliary body using a preloaded guidewire. A controlled cyclodialysis is created, allowing aqueous to flow from the anterior chamber through the stent's 300 micron lumen into the supraciliary space. The CyPass Micro-Stent was approved by the FDA in July 2016.

Nonrandomized series demonstrated that the CyPass Micro-Stent alone and in combination with phacoemulsification reduces mean IOP by 30–35% through 2 years.[28,29] One study showed a 50–75% reduction in mean medication usage after phacoemulsification-CyPass at 1 year.[29] The pivotal COMPASS trial randomized 505 POAG patients with cataract from 24 United States sites to phacoemulsification-CyPass (n = 374) or phacoemulsification alone (n = 131).[30] Medication washout was performed at baseline and 1 and 2 years. Intraoperative randomization (after uncomplicated phacoemulsification), masking of patients and IOP readers, and a predetermined regimen for postoperative medication reinitiation addressed limitations of early studies. A larger proportion of CyPass patients than controls achieved an unmedicated diurnal IOP reduction ≥20% at 2 years (77 vs. 60%, P = 0.001). Control patients required three-fold more medications than CyPass patients at 2 years (0.6 ± 0.8 vs. 0.2 ± 0.6, P < 0.001). Adverse events occurred at similar rates in both groups. Iritis (8.6%), corneal edema (3.5%), hypotony (IOP < 6 mmHg; 2.9%), and IOP elevation ≥10 mmHg above baseline (4.3%) were usually transient in CyPass patients, and no sight-threatening stent-related complications occurred.