Clinical trial shows retinal implant successfully restores vision in 75% of patients
Clinical research has supported the use of an electronic implant to restore sight in patients with advanced retinal degenerative diseases.
A study of the Argus II Retinal Prosthesis System (Argus II), published this week in the British Journal of Ophthalmology , found that the majority of blind people fitted with the implant consistently identified letters and words. This, in combination with the stable, long-term function of the device, represents a significant step in the evolution of artificial sight, the research team said.
It states: “Multiple blind subjects fitted with the Argus II system consistently identified letters and words using the device, indicating reproducible spatial resolution. This, in combination with stable, long-term function, represents significant progress in the evolution of artificial sight.”
The report comes after a clinical trial of the device at 10 centres worldwide, including Moorfields Eye Hospital in London.
“The paper highlights data showing the tremendous potential of the Argus II to restore some meaningful vision in patients that otherwise would have been left blind
Using the ‘bionic eye’ implant, the team tested visually-impaired patients to see whether they could correctly identify single letters and two, three and four-letter words. Of the 21 individuals tested on letter identification, 72% accurately named the letters, compared to only 17% without the implant. For two-letter words there was 75% accuracy and 58% accuracy with four-letter words.
The test group was also able to read letters of reduced size, the smallest measuring 0.9cm at 30cm reading distance. Control data found subjects could not achieve these tasks if the system was disabled or if the spatial resolution provided by the eye chip was artificially scrambled.
The Argus II, manufactured by Second Sight Medical Products, is the first and only approved retinal prosthesis anywhere in the world. It consists of a tiny camera and transmitter mounted in a pair of glasses, which transmits a wireless signal via a small processing device to an ultra-thin electronic receiver that is implanted in the eye and attached to the retina. The electrodes are intended to stimulate the remaining retinal nerves, allowing a signal to be passed along the optic nerve to the brain, which perceives patterns of light and dark spots corresponding to which electrodes are stimulated
The device received its CE Mark in February 2011.
The fact that we are seeing many of our patients being able to recognise large letters, locate the position of objects and more is truly encouraging and beyond initial expectations
Paulo E Stanga, consultant ophthalmologist and vitreoretinal surgeon at Moorfields, said: “This is an amazing leap forward in the field of ophthalmology. After years of research, we are able to offer a viable long-term solution for people suffering from advanced retinal degenerative diseases such as retinitis pigmentosa.”
Commenting on the findings of the latest research, Lyndon da Cruz, consultant retinal surgeon at Moorfields, added: “The paper highlights data showing the tremendous potential of the Argus II to restore some meaningful vision in patients that otherwise would have been left blind. The fact that we are seeing many of our patients being able to recognise large letters, locate the position of objects and more is truly encouraging and beyond initial expectations.”
For information on the study, click here.