Implantable Micropump Regulates Internal Eye Pressure

An implantable microfluid system that can stabilize intraocular pressure efficiently and durably is under development by researchers at Germany’s Fraunhofer Gesellschaft.

Raised or lowered eye pressure diminishes ability to see, and can even lead to blindness in some cases. Until now, no effective long-term treatment has existed.

Current treatment methods do slow disease progression, but they are effective for only a limited period.

For example, in glaucoma, a surgeon creates an additional, artificial effluence from inside the anterior ocular chamber. The problem is that in about one out of every four patients, scarring occurs after the procedure that impedes drainage of intraocular fluid.

In phthisis cases, the physician injects fluids like hyaluronic acid into the eye at regular intervals. This is an unpleasant procedure, to say the least, and still cannot prevent blindness in the immediate or distant future.

Fraunhofer Research Institution for Microsysems and Modular Solid State Technologies (EMFT) is working on a new approach to therapy. They are engineering an active implant designed to efficiently and sustainably regulate eye pressure.

“This way, we can spare the patient from the strain of multiple follow-up procedures, and can preserve the ability to see over a longer timeframe and, in the best case scenario, completely prevent blindness,” says Christoph Jenke, Project Manager at EMFT.

The implant includes a sensor-based pump control, a micro-pump system, an integrated battery for solid state energy, and a telemetry module for data transmission. It can be attached directly to the eyeball.

“Naturally, the patient should not sense it and his or her eye movements must not be restricted in any way,” Jenke clarifies.

Thus, system components had to be miniaturized.

The Munich-based researchers created a tiny (just 7x7x1 cubic millimeters), biocompatible silicon micro-membrane pump with a production rate of 30 microliters per second (maximum). Depending on the disease, it can moisturize the eye or drain intraocular fluid.

Fraunhofer experts use the eye’s natural drainage pathways so that no scar tissue forms. Monitoring at regular intervals, based on a conventional eye pressure measurement ,the attending physician can set the volume of fluid to the desired level on an outpatient basis.

In the long term, plans call for combining the system with an implantable sensor, so that fluids can be regulated automatically.

Currently, the partners are building a functioning demo model that meets all quality specifications with respect to space, energy management, pump control and micro-fluid management on the laboratory scale.