Chip Implant Improves Functional Vision in Retinosa Pigmentosa Patients

Retinosa pigmentosa (RP) is a hereditary degenerative disease that causes loss of vision in humans. The macular area of the retina has the highest concentration of photoreceptors, and this are makes it possible to see visual detail. Retinosa pigmentosa affects the macular photoreceptors (rods and cones) and eventually leads to total blindness in those affected by it. Today, 15 million people worldwide suffer from this disabling condition. But, recently, for nine fortunate souls, a respite from darkness was provided by a three millimeter microchip implant.

Major breakthrough

This medical milestone was the result of the efforts of study proponents from a university in Germany. Tubingen University researchers developed the technology and the implantation procedure that gave the nine RP sufferers the chance to regain their vision. The University’s Institute for Opthalmic Research developed the chip in the hope of improving functional vision of people with retinosa pigmentosa, particularly those who are in the advanced stage of the disease. The 1,500 pixel-microchip is equipped with electrodes and built-in amplifier. It is also light-sensitive.

Improved visual function with state-of-the-art device

In a surgical procedure the microchip was implanted on the eyeball of retinosa pigmentosa patients. The implant was placed just below the retinal surface within the area of the macular region. When an electrical charge was delivered through the tiny device, it stimulated the surrounding tissues.

The results were dramatic in terms of improvement in the functional vision of the subjects who underwent the implant procedure. Visually impaired individuals effectively identified objects and distinguished them from others. The subjects were able to correctly identify familiar fruits place on a table. They were also able to read road signs presented to them. Another breakthrough in improved visual function is in face recognition and they can correctly recognize facial expressions. Tests also revealed improved visual resolution and improved function in various distances. All these might not yet cause better perception of visual detail, but it is enough to improve a person’s ability to orient in space.

How does it work?

This breakthrough provides evidence that sub-retinal implants can help people regain a measure of functional vision without the need for external devices. The reason behind the dramatic improvements in the visual function of people with the implant is the fact that in retinosa pigmentosa, a section of the retina has nerve fibers that still work. By stimulating this area, the nerves can deliver the message to the visual cortex of the brain which then interprets what the person sees. The hope is that stimulation of this nerve via the microchip would lead to recovery of the person’s vision.

Full visual restoration is still not the end result of these trials, but the results are promising. The results of the implant studies are also contributing to the body of knowledge that exists about retinosa pigmentosa, contributing to a better understanding of the disease. Consequently, better treatment options would come out of all these studies and might shed more light on the most effective approach to the management of this incurable disease.

Photo Credit: Human Eye Reflecting the Sun