Retinal Implant Alpha IMS Brings Sight to Blind in New Study (w/video)

Retina Implant AG, a German developer of subretinal implants to help restore sight of people with retinitis pigmentosa, has announced publication of results of a new clinical trial of its Alpha IMS system. Nine blind people received the 3×3 mm wireless microchip implants that feature a 1500 pixel resolution. The implants capture light and in turn stimulate the optic nerve, which delivers visual signal data to the brain.

A distinct advantage of the Alpha IMS is that, unlike other similar devices such as the recently released Argus II, it does not rely on an external camera. Instead, light is detected inside the eye, enabling the patient to look around by moving his eyes rather than the head. It also has a much higher resolution grid and is implanted under the retina, allowing the middle layer of the retina to process the input before it is sent to the visual cortex.

In the study, a majority of the participants had functional vision restored and two of the subjects developed visual ability considerably more substantial than seen in the initial clinical study of the Alpha IMS. Three of the people were able to read large printed letters spontaneously post implantation.

From Retina Implant AG:

The Company’s first clinical trial began in Germany in 2005, where 11 patients suffering from retinitis pigmentosa were implanted with a subretinal microchip below the retina in the macular region. Results from the first trial were published in November 2010 in Proceedings of the Royal Society B, concluding that the implantation of Retina Implant’s microchip was successful in restoring useful vision in patients previously blind due to retinitis pigmentosa. The second clinical trial with a wireless device that allows patients to use the implant outdoors and at home began in May 2010 in Tuebingen, Germany, and has since expanded into the multicentre phase of the trial with implants taking place in Hong Kong and the UK.

Here’s a video of one of the participants recognizing letters placed in front of him:

Electrical stimulation via the 4 x 4 direct stimulation electrode array. Presentation of 5 different letters. The letters I,L,O,T, and V were presented singly to the patient by sequentially activating electrodes with single pulses, using fixed voltage increments above the previously determined threshold. Pulse durations were 4 to 7 ms, with 208 ms between the activation of two electrodes. The sequence was shown only once per run. After one letter, a period up to 45 s was provided for the patient to give his answer, and for the bioengineer on the left (not shown in the movie) to set up the next letter, indicated silently by the investigator. The letters combine to the word “VOLT”, correctly named by the patient but never presented previously to him. 

From the announcement:

The implant used in this clinical study is the result of an ongoing, long-term cooperation of the University Eye Hospitals in Tübingen and Regensburg, the Institute for Microelectronics in Stuttgart (IMS), the Natural and Medical Sciences Institute (NMI) in Reutlingen as well as the Retina Implant AG and Multi Channel Systems (MCS), both located in Reutlingen. MCS the external control electronics for the chip which was developed and produces by IMS. The NMI has been involved in the subretinal implant since 15 years. Apart from the technical development of electrodes for safe long-term stimulationm biostable coating materials and flexible conducting matrials, NMI has been conducting biophysical research for electrical retinal stimulation. This provided guidelines for the design of the implant, feasible stimulus strenths for retinal stimulation, and for reasonable distances between the 1500 stimulating electrodes.

Study in Proceedings of The Royal Society B: Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS

More from Institute for Ophthalmic Research, University of Tübingen: Recent publication on groundbreaking performance of the Tübingen Subretinal Implant

Announcement: Retina Implant AG Announces the Publication of Study Results on its Alpha IMS Implant in Proceedings of the Royal Society B