Eyes wide open!

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Small, biocompatible implants on or in the human body don’t just make it possible to perfectly control vital functions. In the future, they will also prevent people from going blind and allow the blind to see again.

Small, biocompatible implants on or in the human body don’t just make it possible to perfectly control vital functions. In the future, they will also prevent people from going blind and allow the blind to see again.

It will still be a while before eyes can be replaced. But until then, intelligent implants will make it possible to relieve or prevent a number of eye complaints—such as interocular pressure that is too high or too low. In a worst-case scenario, that can lead to blindness. And until now, no therapy that is effective in the long term has been available.

But now researchers at Fraunhofer EMFT have developed an implantable microfluid system that makes it possible to stabilize interocular pressure. It consists of a micropump system, a sensor-based pump control unit, an integrated battery to provide a wireless supply of energy and a telemetry module to transfer data. It is placed directly on the eyeball, but naturally the patient should not feel the microimplant and it should not limit eye movement.

A prerequisite for this solution is extreme miniaturization. Measuring just 7x7x1 cubic millimeters in size, the tiny biocompatible silicon micromembrane pump has a maximum pumping capacity of 30 microliters per second. Depending on the symptoms, it moistens the eye or pumps off aqueous fluid via the eyes’ natural drainage routes.

In the long term, an implatable sensor should regulate the system automatically. Until now, the condition resulted in blindness. The new method, which imitates the natural production of aqueous fluid, could halt the progression of the illness and permanently save people’s eyesight. Right now, the partners are setting up a function demonstrator that satisfies all quality requirements with regard to space, energy management, pump control and microfluidics on a laboratory scale.

Microimplant lets the blind see again

Engineers at Ulm University are focusing on when the retina’s light receptors decay as the result of disease. To minimize blindness, their retina implant takes the place of defective photoreceptors and uses existing communication between the retina and the brain. Admittedly, the connection between the brain and the retina must still exist and patients should not have been born blind. The implant can use electrical impulses to stimulate the retina, and the stimuli are transmitted to the brain. This allows patients to recognize facial expressions and distinguish between objects again.

In a clinical study, the chips have already been tested on approximately 40 patients, many of whom are no longer considered blind.

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A microimplantat allows blind patients to recognize facial expressions and distinguish between objects again. (Image: Frank Hagmeyer/Uni Ulm).