Glaukos iStent Supra® For Intraocular Pressure (IOP) Lowering
The iStent Supra® is a 4mm (less than one quarter inch long) tube with a hole at each end. Made of Polyethersulfone (PES) and titanium, it is intended to be placed in the supraciliary space (next to the uvea). Aqueous fluid should then be able to flow through this tube, out the small holes, and into the uveoscleral space. It can be implanted alone or at the time of cataract surgery through a very small incision. Although it is manufactured by Glaukos in Laguna Hills, California, it is still awaiting FDA approval for use in the USA. “The company projects FDA approval in 2018”. It is, however, currently available in the European Union as an approved device for intraocular pressure (IOP) lowering.
How Well Does the iStent Supra® Appear to Work?
Twelve Month (One Year) Results
Very little has been published about this device. We can, however, gain some knowledge from presentations that have been made at ophthalmology meetings around the globe. A recent presentation at a European meeting provided some encouraging early results. Although the study was small, placement of the iStent Supra® resulted in an IOP reduction of at least 20% as well the ability to discontinue at least one glaucoma medication in 98% of study participants.
Eighteen Month Results
This same group of patients was followed for another six months and these interim results were reported at a conference in Heidelberg, Germany by Dr. Gerd U. Auffarth. Of those eyes that had reached the 18 month mark the average IOP was just over 12mmHg. This compares quite favorably with the pre-treatment average IOP of almost 25mmHg (~50% reduction in IOP)!
Risks of iStent Supra® surgery
Again, as very little has been published about this device we do not really know what risks may be encountered during or after placement of the iStent Supra® glaucoma device. It is reasonable to surmise, however, that the risks would be similar to those encountered with placement of the CyPass Micro-Stent®. These include shallowing of the anterior chamber, post-operative IOP elevation, bleeding in the eye (hyphema), and persistent inflammation.
In theory both the iStent Supra® and CyPass Micro-Stent® should result in similar reductions in IOP and glaucoma medication use. However, we will not know whether the iStent Supra® is an effective surgical treatment of glaucoma until larger and longer term studies are published in peer-reviewed journals.
- Junemann J. Twelve month outcomes following ab interno implantation of a suprachoroidal stent and postoperative administration of travoprost to treat open angle glaucoma. Presented at: The European Society of Cataract and Refractive Surgeons; 2013; Amsterdam, the Netherlands
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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.