The Hydrus™ Microstent (Ivantis, Irvine, CA), like the iStent, is a trabecular microbypass stent. Made of nickel-titanium, it can most easily be thought of as a very long iStent. Whereas the iStent is only 1.0mm long, the Hydrus™ microstent is about as long as an eyelash.
The Hydrus™ Microstent is intended to be placed in Schlemm’s canal. As with the iStent, it directs fluid across the trabecular meshwork and into the Schlemm’s canal. In addition, however, the Hydrus™ Microstent also works as a scaffolding device which keeps a portion of Schlemm’s canal open.
How Well Does It Appear to Work?
As with the iStent, the Hydrus™ implant is intended to be combined with cataract surgery. Unlike the iStent, however, initial results obtained two years after surgery appear to be promising. As of the time this was written the device is still under review by the FDA.
In the HYDRUS II study patients with open angle glaucoma underwent placement of a Hydrus™ implant at the time of cataract surgery. Two years out from surgery 73 percent were able to maintain intraocular pressure control without the use of drops. This compares to only 38 percent who were drop-free after cataract surgery alone. Additionally, 80% of those with a Hydrus™ implant achieved a 20% reduction in IOP compared to only 46% in those who underwent cataract surgery alone.
Who Will Likely Benefit from the Hydrus™ Microstent
As with the iStent, the Hydrus™ implant will most likely be indicated for those with mild, controlled glaucoma undergoing cataract surgery. Unlike the iStent (which seems only to financially benefit the surgeons who implant it along with shareholders of Glaukos), based on initial reports I expect patients who receive the Hydrus™ implant will benefit in a meaningful way.
About the Author: David Richardson, MD
Medical Director, San Marino Eye
David Richardson, M.D. is widely recognized as one of the top cataract and glaucoma surgeons in the US and is among an elite group of glaucoma surgeons in the country performing the highly specialized canaloplasty procedure. Morever, Dr. Richardson is one of only a few surgeons in the greater Los Angeles area that performs Micropulse® "Cyclophotocoagulation" (MP3) glaucoma laser surgery. Dr. Richardson graduated Magna Cum Laude from University of Southern California and earned his Medical Degree from Harvard Medical School. He completed his ophthalmology residency at the LAC+USC Medical Center/ Doheny Institute. Dr. David Richardson is also an Adjunct Assistant Professor of Clinical Ophthalmology at Keck School of Medicine of USC. Twice weekly, he treats veterans at the VA Greater Los Angeles Veterans Healthcare System.