The retrospective case series included 59 glaucomatous eyes with cataracts and severe visual field loss. At baseline, the medicated mean IOP was 19.3 mm Hg and the mean number of topical glaucoma medications used per eye was 2.3. In 49 eyes followed for 24 months after iStent implantation and concomitant cataract surgery, mean postoperative IOP decreased to 14.9 mm Hg while the mean number of glaucoma medications used per eye declined to 1.6. In a consistent cohort of 32 eyes with available data through three years postoperative, the IOP reduction was maintained. At three years, this cohort achieved a mean postoperative IOP of 14.1 mm Hg, from a baseline mean medicated IOP of 18.1 mm Hg, and a 28 percent reduction in mean glaucoma medications used per eye from 2.44 preoperatively to 1.75.
“While many prior studies have documented the clinical benefits of combining iStent implantation with cataract surgery in glaucoma patients who are in the mild to moderate stage of the disease, we believe this is the first published study to focus on its use in severe glaucoma patients undergoing cataract surgery,” said John Berdahl M.D., a South Dakota-based ophthalmic surgeon and one of the article’s authors. “Our study showed that severe glaucoma patients experienced sustained reductions in IOP and medication use through three years postoperative.”
According to the study authors, no intraoperative complications were noted. Among the 59 eyes in the series, four required additional surgery.
Glaukos is the study sponsor and the pioneer of Micro-Invasive Glaucoma Surgery, or MIGS. The company’s iStent was approved by the U.S. Food and Drug Administration (FDA) in 2012. Inserted through a small corneal incision made during cataract surgery, the iStent is designed to reduce IOP by restoring the natural physiological outflow of aqueous humor through the trabecular meshwork and into Schlemm’s canal, the eye’s primary drainage channel.
“Although the iStent is currently indicated for use in the United States during cataract surgery in mild to moderate glaucoma patients, this study offers important insights into the potential for our technology platform to ultimately serve a full range of glaucoma disease states and progression,” said Thomas Burns, Glaukos president and CEO.
Glaukos announced recently that it has submitted an Investigational Device Exemption application to the FDA, seeking authorization to study its iStent infinite Trabecular Micro-Bypass System. The iStent infinite is designed for use as a standalone procedure to reduce IOP in refractory or severe glaucoma patients. It includes three trabecular bypass stents preloaded into an auto-injection system that allows the surgeon to inject stents across a span of five to six clock hours around Schlemm’s canal.
Glaucoma is characterized by progressive, irreversible and largely asymptomatic vision loss caused by optic nerve damage. There is no cure for the disease and reducing IOP is the only proven treatment. Based on analysis of population-based surveys, medical claims data and other statistics, the company estimates that there are approximately 5.4 million people in the United States with primary open-angle glaucoma, the most common form of the disease.
Glaukos develops and commercializes glaucoma treatment products and procedures. The company pioneered Micro-Invasive Glaucoma Surgery, or MIGS, to revolutionize the traditional glaucoma treatment and management paradigm. Glaukos launched the iStent, its first MIGS device, in the United States in July 2012 and is leveraging its platform technology to build a comprehensive and proprietary portfolio of micro-scale injectable therapies designed to address the complete range of glaucoma disease states and progression. The company believes the iStent, measuring 1 mm long and 0.33 mm wide, is the smallest medical device ever approved by the FDA.