Somewhere between 25 and 30 million people suffer from age-related macular degeneration (AMD) around the globe, and it is considered one of the main causes of blindness in adults who are middle-aged to older. Nano Retina, a start-up located in Israel, recently announced Bio-Retina which is a tiny collection of photodetectors that are able to be implanted just beneath the eye’s retinal surface. Sometime in 2013 the technique is set to begin clinical trials. According to the company, Bio-Retina will restore vision to any AMD sufferer nearly instantaneously following the implantation process which has been deemed “easy”.

The tissue that lines the rear-inside surface of the human eye is the retina, and it is light sensitive. The retinal tissue is arranged by layers, and it is here the rods and cones, or photoreceptors, of the eye are located. These rods and cones are found beneath layers of ganglia and neurons which are all interconnected by the brain’s synapses. Here, the ganglia perform the lower-level process in visual information, while the neurons transmit the entire picture to the optic nerve.

Age-related macular degeneration is caused as the retina’s central region, or macula, begins to breakdown and deteriorate. A small location inside the retina provides a person with their central vision and allows you to see even the smallest of details. As AMD develops, it begins to destroy the ability of the cones and rods to convert the light into the proper signals to be transmitted by the optic nerve. An AMD-affected retina has optic nerves that are still fully functioning, in addition to other retinal subsystems that allow the neural signals to move from the rods and cones along the optic nerve. However, if the rods and cones are not functioning, there are no neural signals that are light-generated for the retina to transport. Patients who develop AMD will retain a small portion of their peripheral vision; however their central vision will disappear rather quickly over time. AMD eventually ends in legal blindness; however, total blindness is rather common also. Currently there are no treatments for AMD that are effective.

Bio-Retina

That is, no effective treatments until now! With Nano Retina’s development of the Bio-retina, a very small microchip is implanted into the patient’s eye and glued directly to the retina during a procedure that is described as minimally invasive. Although, the process does not treat AMD, it does give patients relief from the blindness caused by AMD. Under local anesthesia, a tiny slit is cut into the eye and the microchip is pressed against the damaged macula during the implantation process.

This new system, Bio-Retina uses the eye’s own optical system (iris, lens, and focusing and pointing musculature). The system is made up of a circuit that is integrated with a grid of microelectrodes, photodetectors, and microelectronic circuitry designed to replace natural photoreceptors in the eye and transport visual information from the healthy retinal structures along the optic nerve and to the visual centers in the brain. You will not be required to learn how to interpret images that are jumbled, because the photodetectors will measure the light that is incoming into a specific spot on the image, and proceeds to stimulate the neurons in the optical nerve immediately under the spot where the light would have initially hit. It is very common for patients to regain their sight immediately, and it will feel rather normal. Currently, the images are available in a grayscale only; however, implants that offer color are not beyond technology.

As the first clinical studies are going to begin next year, the studies will be using a pixel grid that is 24 x 24 with 576 photodetectors. However, it has been suggested that the more advanced studies will have pixel grids that are 72 x 72 with 5184 photodetectors. Approved for use only in Europe, there is a product on the market called the Argus II retinal implant and it uses a pixel grid that is only 8 x 8. As you can see, the Bio-Retina is in a class of its own.

All sounds good, but there is still one small issue. In order to be able to detect light and stimulate the visual neurons electrically, a source of electrical power needs to be present. The good news is that Nano Retina did a good job at elegantly solving the dilemma. Situated toward the eye’s lens, the implanted microchip was equipped with a tiny photovoltaic cell. Patients who receive the implant can once again wear normal eye glasses for the most part. The exception is that the new glasses include a laser that is batter operated and points straight into the eye. Although the small laser light is harmless to the eye and not visible, it can charge the photovoltaic cell by delivering as much as three miliwatts of electric; thus – providing a surplus of energy to power the implant.

One devastating blow that affects AMD sufferers wanting to finish their career or begin retirement is blindness that follows a life full of perfect vision. Since sight is so heavily incorporated into how we perceive the world around us, the loss of sight is beyond the realm of what most of can or want to comprehend. Hopefully the future will see developments for more research on the subject so future generations will never have to worry about developing AMD.