Subconjunctival implant: 2-year data

San Francisco-Two-year data on a subconjunctival implant (XEN, Aquesys) suggest that the device is both safe and effective in lowering IOP in both refractory glaucoma and early stages of the disease. Results from the multicenter, international study were presented by Steven Vold, MD.

“This is quite an elegant procedure,” said Dr. Vold, of Vold Vision, Fayetteville, AR. “It bypasses all the potential outflow blockages and is conjunctival sparring in that it does not require a conjunctival incision. We are hoping it can treat not only late-stage glaucoma but also earlier stages of the disease.”

A total of 20 surgeons at 16 sites in seven countries implanted the minimally invasive ab interno device in 107 patients. The mean medicated IOP before surgery was 21.8 mm Hg and researchers followed the patients for 24 months. Outcomes included mean IOP, IOP change, and reductions in medication and safety.

XEN is a permanent transscleral aqueous drainage tube made of gelatin that connects the anterior chamber to the subconjunctival space. It is injected via a 27-gauge needle and does not require either a conjunctival incision or a flap. The device is designed to create a gentle and diffuse dispersion of aqueous into the non-dissected Tenon’s and subconjunctival space. Rabbit models also suggest that the device may improve the lymphatic flow, Dr. Vold noted.

Two years of experience suggests that the device works as designed. The mean postop IOP fell to 15.9 at 12 months, 15.1 at 18 months, and 14.2 at 24 months. The mean reductions in IOP were 27% (–5.9) at 12 months, 31% (–6.8) at 18 months and 35% (–7.6) at 24 months.

Patients were taking a mean of 2.8 glaucoma medications before surgery. After 12 months and 18 months, medication use was reduced by 64%. At 24 months, medication use was 57% below the preop baseline. There were no major adverse events reported during the first 2 years and only seven eyes (6%) had another surgical glaucoma procedure.

“We are very consistently getting pressures in the mid-teens and IOP lowering of 25% to 35% over 2 years with very minimal adverse events,” Dr. Vold said. “This is quite efficacious and a very promising technology.”

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