Investigators tested the performance of a second generation implantable IOP sensor (Eyemate-IO; Implandata) in patients with primary open-angle glaucoma (POAG).

Study design

This European multicentered, prospective, noncomparative, open-label study investigated the safety and performance of the Eyemate-IO in 22 patients with POAG who were undergoing cataract surgery.

The device consists of an integrated circuit bonded to a gold microcoil sealed in a silicon ring that is implanted in the sulcus. It requires an external handheld reader to be placed within 5 cm of the eye to power the sensor, enable the IOP measurement and transfer the data to the reader. Patients were trained to gather at least four readings/day. The data was compared to follow-up visits with Goldmann applanation tonometry. Surgery complications and postoperative adverse events were recorded through 12 months.

Outcomes

Surgical complications included five patients with iris prolapse, five with pigment dispersion and two with a flat anterior chamber. Postoperatively, there were two cases of fibrinous inflammation, one corneal decompensation and one intractable IOP requiring additional glaucoma surgery.

The Eyemate measured, on average, 3.2 mm Hg higher than the Goldmann. There were two instances that required recalibration of the sensor: one after YAG laser and the other after ultrasound biomicroscopy.

Limitations

The study comprised a small sample size. There is a learning curve associated with the implantation and each surgeon only had 1 or 2 patients included in the study. Follow-up time was relatively short; longer follow-ups are necessary to make sure the device remains safe and accurate.

Clinical significance

The Eyemate-IO can provide continual diurnal and nocturnal IOP measurements. Since it is not affected by corneal factors such as thickness or hysteresis, it may provide better accuracy than Goldmann applanation tonometry. This device has received regulatory approval in the European Union, but is not currently approved in the United States.