Retinal prostheses: promising results

Pubblicato il

Thursday, 21 April 2016

Argomento

Surgical Area

Data on the first implanted patients published.

Published in 'Clinical and Experimental Optometry' the results of the study "An analysis of observer-rated functional vision in patients implanted with the Argus II Retinal Prosthesis System at three years'.
In this three-year observational study, the following was used for the first time FLORA (Functional Low-Vision Observer Rated Assessment), a multifunctional test designed specifically for patients implanted with retinal prostheses, and with profound visual impairment. This test was used to assess visual function in 26 blind patients implanted from 2006-2009 and the use of Argus II during a series of daily activities.
The Retinal Prosthesis System Argus® II (Second Sight) is an implantable medical device dedicated to people who have become blind due to Retinitis Pigmentosa.
Argus II is available at accredited centres in Austria, Canada, France, Germany, Italy, the Netherlands, Saudi Arabia, Spain, Switzerland, Turkey, the UK and the USA.
In Italy, it is currently covered by the national health service in Tuscany and Veneto and is available in two centres: the Azienda Ospedaliera Universitaria Careggi in Florence and the Azienda ULSS 15 Alta Padovana in Camposampiero (PD).
Argus® II uses electrical stimulation to bypass dead cells and stimulate the remaining viable retinal cells by inducing visual perception in people with severe or profound outer retinal degeneration. The Argus II works by converting images captured by a miniature camera mounted on the patient's glasses into a series of small electrical impulses, which are transmitted wirelessly to an electrode array implanted on the surface of the retina. These impulses are intended to stimulate the remaining cells of the retina, resulting in the perception of light patterns in the brain. The patient then learns to interpret these visual patterns, thus regaining some visual function. The system is software-controlled and upgradeable, which can lead to better performance as new algorithms are developed and tested. The results of the study "An analysis of observer?rated functional vision in patients implanted with the Argus II Retinal Prosthesis System at three years' show an improvement in both visual performance and patient autonomy as well as good tolerance and long-term system reliability.
A significant improvement in visual function was evidenced with the device switched on for 24 out of 35 tasks tested (69% of tasks). For the new activities (26%), no significant changes were observed. Results were less positive for only 2 activities (6%). A control with the device switched off allowed a placebo effect to be excluded.
This publication shows that tasks that are difficult or impossible for blind people to perform, such as locating and crossing a pedestrian crossing independently or visually identifying people, are made possible when using the Argus II device. Furthermore, the publication indicates that the system is reliable and well tolerated in the long term.