What do the numbers tell us about the iStent?
As a cataract surgeon, my primary concern is managing a patient’s cataract. I want to provide my patient with the best vision and fewest postoperative issues possible. When I finish a case that in my mind went perfect, do I really want to tilt the patient’s head, tilt the microscope and deal with a glaucoma stent?
It is easy to convince ourselves that if a patient with concomitant glaucoma is controlled on drops, we should leave well enough alone. But my feeling is I have a responsibility to help these patients have better IOP control and relieve them of topical drops. Patients from 30 to 80 years old, whether they are truck drivers or physicians, are always going to miss some drops. And experience with the iStent trabecular micro-bypass stent (Glaukos) has shown increasingly that it reduces pressure, gets patients off drops and does not negatively impact cataract surgery outcomes.
Recent and significant improvements in real-world results
The initial U.S. pivotal study for the iStent was submitted to the FDA in 2008. It compared a total of 240 eyes with mild to moderate open-angle glaucoma that underwent either cataract surgery alone or cataract surgery in conjunction with a single iStent. The primary efficacy measure was unmedicated IOP less than 21 mm Hg at 1 year, and 72% of eyes with the iStent met this goal, compared with 50% of eyes that underwent cataract surgery alone. The iStent achieved the necessary endpoints, the FDA approved the device, and a new category for treating glaucoma was launched.
One of the most exciting aspects of the evolution of microincision glaucoma surgery is the continued and significant improvement in clinical results that we have seen since then. Mark Gallardo, MD, presented his clinical results at the 2016 American Society of Cataract and Refractive Surgery meeting. His consecutive case series of 72 eyes of 48 patients were all implanted with a single iStent at the time of cataract surgery. Mean IOP was 15.3 ± 3.2 mm Hg at baseline, and 75% were taking two to four medications. At 6-month follow-up, 86% had met the surgical goal of IOP less than 14 mm Hg, and medication reduction was greater than one…..