Implanted for the first time in Italy to a blind seventy-year-old a last generation artificial retina. The intervention, carried out by Professor Stanislao Rizzo, director of the Ophthalmology Unit of the Agostino Gemelli IRCCS University Polyclinic Foundation and Ordinary of Ophthalmology Clinic at the Catholic University campus in Rome, lasted just two hours. Upon awakening the patient, suffering from a severe form of retinitis pigmentosa that had caused the loss of vision, was already able to perceive light.
Professor Rizzo was a pioneer in artificial retinal implants: in 2011 he was the first to use Argus, the first retinal prosthesis used in a blind patient. “We are really happy to start this new experience – comments Professor Rizzo – which is the result of teamwork, for which I thank all my team, made up of passionate and enthusiastic people. This new artificial retina should ensure better results than the previous ones, being equipped with more than 400 electrodes, many more than the Argus which had 60. The idea of giving back even a semblance of sight to people who have lived in the dark for years, it is any doctor’s dream. The operated patient already sees the light and this is truly incredible. For now, the artificial retina is only indicated for patients suffering from retinitis pigmentosa (a pathology that affects about 150,000 Italians) in the most advanced stages of the disease, i.e. people who have completely lost sight in both eyes, a condition that affects about 1,000- 1,500 Italians. The selection criteria to enter this experimental trial are for now very strict and restrictive “.
The new artificial retina (NR600) was developed by the start-up Nano Retina, which has its headquarters in Herzliya, Israel’s ‘Silicon Valley’, near Tel Aviv. The one carried out at Gemelli is the sixth implant (the first in Italy) in humans of the new device, after those carried out last year in Israel and Belgium (the patients operated so far are aged from 59 to 81 years). In Europe it is being tested in a multicentre clinical trial, which will involve about twenty patients, aimed at obtaining CE approval of this innovative retinal prosthesis.
A concentrate of the highest technology in a few millimeters
This high-tech solution is the result of over a decade of research. The implant, as big as the tip of a pencil (5 mm in diameter x 1 mm thick), is placed by a super expert in retinal surgery over the surface of the retina and the three-dimensional electrodes of which it is composed, penetrate between the cells retinal cells, taking the place of photoreceptors (the specialized cells that allow us to ‘see’) and activating the ganglion cells with their impulses, which transmit information to the brain, making it travel along the optical pathways. To activate the 3D micro-electrodes, the patient must wear special glasses that send an infrared ray to the device, which feeds it, through a tiny photovoltaic system (two photovoltaic cells) with which it is equipped.
Light stimuli translated into electrical impulses
The software and hardware contained in the glasses also control and modulate (as through a Morse alphabet) the light stimuli that arrive at the electrodes, translating them into electrical impulses which will then convey, along the optical pathways, the information to the brain. “In the last phase of retinitis pigmentosa – explains Professor Stanislao Rizzo – the photoreceptors (cones and rods) are completely destroyed; but some cells, such as retinal ganglion cells, survive. They are important cells because they transmit information from photoreceptors to the brain. The 3D electrodes replace the photoreceptors, the specialized cells that make up the first part of the optical pathways and transmit information to the ganglion cells ”.
As seen with the artificial retina
Implanting this device restores some of the retinal function, but does not restore sight. The patient can return to ‘seeing’ the light immediately after implantation, but the rehabilitation program is usually started a couple of weeks after surgery. This involves a series of exercises to be administered to the patient who relearns to see through this sort of bionic eye; in addition, the electrode stimulation is fine-tuned to obtain the best possible vision. At the end of this special training the patient will be able to distinguish the shape of objects, recognize movement, will learn to interpret these new images, which he sees in black and white and pixelated; finally, thanks to neuronal plasticity, the brain will gradually learn to distinguish and recognize these objects. This guarantees the patient a better social interaction and restores a certain autonomy in the activities of daily life.
For which patients the artificial retina is indicated
“For this type of implant – explains Professor Rizzo – careful selection of the candidate patient is essential, who is framed through a series of psychological interviews; this serves to evaluate both his potential to continue along a rehabilitation path that will engage him for a long time, and his expectations. Because this system does not return a normal vision but a ‘bionic’ artificial vision. The patient must be prepared for the fact that what he will see is a reconstruction through ‘phosphenes’, flashes of light, which compose a pixelated image. The overall view is obtained from the work of the 576 electrodes present in the device, whose parameters must all be configured with a lot of patience, through a special application “.
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