Positive outcomes support two trabecular bypass stents

Interim results from a prospective study support the safety and efficacy of micro-invasive glaucoma surgery with implantation of two trabecular bypass stents (iStent, Glaukos) for reducing IOP and medication burden in phakic and pseudophakic eyes with mild-to-moderate open-angle glaucoma uncontrolled on one ocular hypotensive medication, said David F. Chang, MD.

Chicago-Interim results from a prospective study support the safety and efficacy of micro-invasive glaucoma surgery with implantation of two trabecular bypass stents (iStent, Glaukos) for reducing IOP and medication burden in phakic and pseudophakic eyes with mild-to-moderate open-angle glaucoma uncontrolled on one ocular hypotensive medication, said David F. Chang, MD.

Speaking on behalf of his co-investigators in the Micro-invasive Glaucoma Study Group, Dr. Chang presented outcomes from 12 months of follow-up in an ongoing 2-year study. Eligible patients had IOP >18 mm Hg while on one medication preoperatively, IOP >22 mm Hg after medication washout, and a CD ratio ≤0.9.

Data were analyzed from 28 eyes of which most were phakic. At 12 months, IOP was reduced from baseline by an average of 43%, by at least 40% in 61% of eyes, and by at least 20% in 89% of eyes. In addition, a need for medication was eliminated in 25 eyes, and 89% of eyes achieved IOP of 18 mm Hg or less with no medications.

Best-corrected visual acuity was maintained or improved in 25 eyes, and the only adverse event/complication was a small hyphema in one eye at week 1 that resolved by 1 month.

“The results of the U.S. pivotal trial of this device have already been published and showed that eyes undergoing phacoemulsification with stent implantation had significantly greater reductions in IOP and medication use compared with the control group having cataract surgery alone,” said Dr. Chang, clinical professor of ophthalmology, University of California, San Francisco. “However, it was difficult to sort out how much of the benefit observed in the combination surgery group was from the cataract operation alone.

“Since the current trial enrolled all phakic and pseudophakic patients, there was no concurrent cataract surgery to confound the results,” he said. “The outcomes are exciting, and the safety outcomes are also encouraging as they suggest the procedure should be safe in the hands of cataract surgeons.”

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