For the first time the United States Food and Drug Administration (FDA) has approved a retinal prosthesis that is able to restore some degree of sight to people suffering from certain types of blindness. The new technology allows them to orient themselves in a room, negotiate city sidewalks, and might even one day even enable them to read.
Ever since Google’s announcement of the launch of its first smart glasses, wearable technologies have been all the rage. However, far from being mere futurist accessories, some of these products incorporate state-of-the-art technology and can bring about real improvements in people’s lives.
After twenty years of research, California-based company Second Sight has developed a pair of glasses which, coupled with a prosthesis implanted on to the retina, enable some blind people to rediscover a degree of physical independence. The product, known as Argus II, is the first-ever retinal prosthesis to be granted market approval by the FDA for patients in the United States. The artificial retina sends messages through the optic nerve to the brain, allowing people who have lost their sight due to deterioration of the retina to regain partial sight, recovering in particular their sensitivity to contours, colours and contrasts. The medical device is designed to make people who suffer from this type of blindness more independent in their daily lives, and the researchers also hope to extend the system to help those suffering from degenerative blindness linked to old age and even people blind from birth.
Bionic, connected eye
The Argus II has taken more than twenty years to develop. It incorporates sophisticated technologies based partly on mass market accessories. The prosthesis, made up of around sixty electrodes, is implanted on to the patient’s retina. The other two elements in the Argus II system are a pair of sunglasses fitted with a video camera and a Texas Instruments digital signal processing unit. The camera used is very similar to the model initially developed for smartphones, and the chip which enables light to be registered is inspired by electronic signal processors originally developed for games consoles. The video-glasses record real images, which are processed by the miniature computer – worn like a shoulder bag – and then transmitted by wifi to the electrodes, which stimulate the retina by means of electrical signals. The prosthesis, which has been tested by a number of patients for the last six years, is implanted permanently in order to avoid multiple invasive surgery. The other parts of the system – glasses, processor, etc. – are currently undergoing miniaturisation.
Ongoing adaptations to meet a variety of needs
Following FDA approval in February this year, Second Sight has announced that it is providing the Argus II to twelve US medical centres at a cost of $145,000 per unit. The company, which has just raised over $200 million in funding, hopes to undertake ongoing improvements in the scope and use of the product. Given that the Argus II relies on brain capacity to recreate images from memorised vision, the system is currently intended specifically for use by people suffering from a degenerative condition of the retina known as retinitis pigmentosa, and is not designed to help those who have been blind from birth. In addition, the system can only be used by sufferers who are 25 years of age or over who still retain sensitivity to light, which adds up to around 12,000 US citizens. The company nevertheless also intends to help alleviate a wider range of cases of blindness, for example the two million US citizens who suffer from degenerative blindness linked to old age. Second Sight is now working to develop electrodes that can be placed directly on the cerebral cortex as this would make the prosthesis easier to implant and would provide better vision on a daily basis.