Investigators evaluated the safety and efficacy of the CyPass supraciliary microstent in patients with refractory open-angle glaucoma.
Study design
All 20 patients had refractory glaucoma (maximum medication and failed prior glaucoma surgery) and were treated at Moorfields Eye Hospital. Previous interventions included trabeculectomy, aqueous shunt, needling, cyclodiode and ab interno gel implant. The CyPass was implanted with (30%) or without (70%) combined phacoemulsification.
Outcomes
At 12 months, mean IOP decreased by 34% from baseline to 15 mm Hg (P=0.01). Mean medication burden decreased by 56% to 1.2 medications.
Two patients required subsequent insertion of an aqueous shunt. Adverse events were infrequent: 20% had a transient IOP spike above 30 mm Hg, 15% had transient hyphema, 10% had anterior chamber inflammation (all had a history or uveitis), 5% developed CME, and 5% had hypotony. No patient lost 2 or more lines of vision, had a suprachoroidal hemorrhage or retinal detachment.
Limitations
This study was designed to look at the immediate and short-term (12 month) risks of supraciliary stenting and a longer study is needed to evaluate long-term effectiveness. This was a retrospective study so the decision to adjust medication or perform additional surgery was at the discretion of the treating physician and was not controlled. There was an unusually high number of uveitic glaucoma patients (50%) in this study.
Clinical significance
This is an important study that proves that supraciliary stenting is a relatively safe procedure and worth further investigation as a potential alternative for refractory glaucoma, even those with severe disease and significant VF loss (mean deviation in this study was 12.1 dB).
Currently, the CyPass is the only FDA approved supraciliary stent in the United States, and is only approved in combination with cataract surgery for mild to moderate open-angle glaucoma. This study suggests that its applications could be broadened.