The intervention coordinated by the director of the Ophthalmology of the Gemelli Polyclinic, Stanislao Rizzo, one of the pioneers in artificial retinal implants. The technique for now indicated only in severe cases of retinitis pigmentosa
The retinitis pigmentosa a terrible disease, of genetic origin: the retina of both eyes slowly and progressively degenerates, reducing its ability to transmit visual information to the brain. In the most serious cases it leads to blindness. One of the greatest dreams of science to restore sight to those who have lost it and in Rome, at the Agostino Gemelli University Hospital, a step forward has been made in this direction. TO a 70-year-old blind person, with a severe form of retinitis pigmentosa, was implanted an artificial retina of the latest generation, equipped with over 400 electrodes and the size of a pencil tip. The intervention, coordinated by Stanislao Rizzo, director of the Ophthalmology Unit at Gemelli and full professor of Ophthalmology at the Catholic University campus in Rome, lasted two hours. Upon awakening, the patient was able to perceive light. A similar intervention was carried out in 2018 at the San Raffaele Hospital in Milan.
Study on twenty patients in Europe
The artificial retina (NR600) produced by the Israeli company Nano Retina. The sixth implant (the first in Italy) performed at Gemelli in the man of the device. In Europe in progress a multicenter clinical study, involving about twenty patients, aimed at obtaining CE approval for the high-tech prosthesis, the result of research lasting over 10 years. The implant, 5 mm in diameter and 1 mm thick, is positioned above the surface of the retina and the three-dimensional electrodes of which it is composed take the place of the photoreceptors (the specialized cells that allow us to see), activating with their impulses ganglion cells, which transmit information to the brain. The patient must wear special glasses that power the device with an infrared ray. The software and hardware contained in the glasses control and modulate (as in a Morse alphabet) the light stimuli that reach the electrodes, translating them into electrical impulses which will then convey the information to the brain.
Severe forms of retinitis pigmentosa
In the last phase of retinitis pigmentosa, the photoreceptors (cones and rods) are completely destroyed; but some cells, such as the ganglion cells of the retina, survive – explains Professor Rizzo -. They are important cells because they transmit information from photoreceptors to the brain. 3D electrodes replace photoreceptors, the specialized cells that make up the first part of the optical pathways and transmit information to ganglion cells. Stanislao Rizzo was a pioneer in artificial retinal implants: in 2011 he used the Argus retinal prosthesis in a blind patient. 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 expert emphasizes -. The idea of giving back even a semblance of sight to people who have been living the dream of any doctor for years in the dark. The operated patient already sees the light and this is truly incredible. The NR600 artificial retina indicated only for patients with severe forms of retinitis pigmentosa, ie people who have completely lost sight in both eyes, a condition that affects over a thousand Italians.
Rehabilitation begins after 2 weeks
Implanting the device restores some of the retinal function, but does not restore sight. The patient can perceive the light after surgery (as happened to the 70-year-old operated on for Gemini), but in general the rehabilitation program starts after a couple of weeks. Through specific exercises, the patient relearns to see through a sort of bionic eye; also comes the stimulation of the electrodes was gradually improved to get the best possible view. At the end of this training, the patient distinguishes the shape of the objects, recognizes the movement, learns to interpret the new images, which sees in black and white and pixelated; finally, thanks to neuronal plasticity, the brain slowly learns to distinguish what is in front of it. The goal, in addition to restoring a partial view, to improve social interactions and make the person as autonomous as possible in daily activities.
The implant does not return normal vision
The selection criteria to enter this experimental trial are very strict and restrictive – says Rizzo -. For this type of implant, in fact, an accurate selection of the candidate is fundamental, who is framed through a series of psychological interviews; this serves to evaluate both its potential to continue along a rehabilitation path that will keep him busy for a long time, both his expectations. Because the implant does not return normal vision, but offers an artificial, “bionic” 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 overview is obtained from the work of the electrodes present in the device, whose parameters must all be configured with patience, through a special application. An artificial retina was also produced (and tested) in Italy: the result of the work of researchers from the Institute of Technology in Genoa.
October 26, 2021 (change October 26, 2021 | 4:05 pm)
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