Retinal prosthesis are devices that allow those who have become blind due to some conditions to have their vision partially restored. Though very useful for perceiving shape and movement, the current generation of retinal prosthesis doesn’t have a high enough resolution for their users to effectively read. During a recent study researchers flashed braille patterns directly onto a patient’s retina instead, thereby allowing him to read.

The physical prosthesis used in this study is actually not bleeding edge new, despite being a fairly remarkable piece of technology. Developed by medical device company Second Sight, the Argus® II Retinal Prosthesis System consists of a 6 x 10 electrode array implanted on a patient’s retina, connected to a visor that combines a camera, onboard computer for video processing, and inductive coil for wireless power/data transfer to the electrodes.

Unfortunately, with a field of vision composed of sixty pixels it is exceedingly hard to make out details like the small letters on a page of text, or even a large ones on street sign.  While future stimulation devices are predicted to have higher resolutions, researchers wanted to exploit the capabilities of current prosthetics to allow the patient to read now.

second sight retina e1354312740896 Blind man reads braille patterns with his eyes, using implanted retinal prosthesis

Electrode array implanted on the retina

The patient involved could already read braille in the more traditional tactile way. Researchers bypassed the camera and directly stimulated braille patterns onto his retina, flashing each letter for half a second before moving onto the next. While he was only shown words ranging from one to four letters long, he still recognized 89% of them right overall.

Authored primarily by Second Sight, researchers from Brigham Young University in the U.S. as well as the Institut de la Vision and National Ophthalmology Hospital  Paris, France also participated in the study. It was carried out in the Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, in Paris, France.

Sources:
frontiersin.org
2-sight.eu