An Update on the Bionic Eye Project Funded by An Update on the Bionic Eye Project Kiera Young Bionic Eye Project Presentation: will touch on, what a bionic eye is and provide an overview of what CERA has been involved in since the first bionic eye project that started in 2012. What is the bionic eye? What does it mean? Sounds very futuristic and is quite a general term. Researchers working v.hard to develop a retinal prosthesis device that will one day be commercialised and aid patients who have lost their sight.

What is a Bionic Eye? Visual Prothesis (implant) Uses electrical or light energy to stimulate the visual pathway Location of implant varies Bionic eye devices = visual prosthesis Use light electrical energy to stimulate an area of the visual pathway Location of the bionic eye can vary between groups and can be implanted into several locations along this pathway. Retina = where ours is implanted and where our research is focused Courtesy: L. Ayton

Retinal Prosthesis Locations Image = cross section of the layers of the retina Imagine 3 layers – side on view 1st = Retina – receives the light input that enters our eye 2nd = Choroid – provides nutrients to the retina 3rd = Sclera – white outside layer of our eye Bionic eyes can be place: Epi-retinal region = on top of retina (in front of the first layer) Sub- retinal = under the retina (under the first layer) Supra-choroidal space = under the second layer, the choroid – where our bionic eye is implanted Aim of bionic eyes placed in these 3 areas is to restore some level of vision to people who have gone blind from retinal degenerative diseases. At this stage our research focuses on a condition called Retinitis pigmentosa (RP) Ayton et al, Plos One, 2014

Who is most suited for bionic eye implants? Retinitis Pigmentosa RP = photoreceptors within the retina degenerate - Characteristics signs = dark pigmentation in the periphery of the retina - Affects patients quite early reducing their peripheral vision first + light sensitivity - Progresses to degeneration of central vision around late teens/early 20s-30s - Most RP patients dx legally blind/completely blind by late 20s-early 30s - Progression varies greatly from px to px - Rare 1:3000-1:5000 dx - Inherited, often skipping a few gens - Spontaneous dx and no fam hx - RP can accompany other syndromes and diseases – eg ushers syndrome - Currently no cure or treatment Images Courtesy: NIH

How does it work? How the bionic eye works - implant in retina - A few more components that make up the bionic eye, which all work together to process an image Image: set up of the implant= 1. A video camera fitted to pair of glasses. Captures the continuous image the patient looks at 2. Data from the camera is sent to an external processing unit the px carries/wears, sends information to receiver/stimulator 3. The location of the receiver varies between research groups. Ours is implanted under the skin in the area behind the ear on the side of the head. Once the stimulator receives info from PVP it sends signals to the retinal implant which stimulate and activates the surviving cells of the retina retina. 4. This stimulation of the retina sends signals down the visual pathway to the visual cortex of the brain which interprets the signals as phosphene vision Phosphene vision Do not regain normal vision Artificial vision = phosphene vision Device produces this by using electrical/light energy that enters eye to stim vis pathway and generate the artificial type vision as a series of lights. Phosphenes = grey scale, do not provide colour or detail. Used to detect an object in your pathway. Participants undergo intensive training – get their brain use to receiving visual input again – most haven’t used vis pathway in a while. Participants have to learn how to interpret this new artificial phosphene vision.

BVA Prototype Clinical Trial 2012-14 First bionic eye trial = 24Ch percutaneous plug study. Implant had 24 electrodes on a 2x1cm silicon plate. Proof of concept, prototype trial to determine: 1. Safety and feasibility 2. Stability of device 3. Determine if a phosphene could be produced, and could a participant with a severely damaged retina see, interpret, and use the phosphenes 2 x 1 silicon plate with 24 electrodes. Connected to percutaneous plug exposed through skin behind ear – connected px to computer in labs Study = 3 participants, RP, light perception 2.5yrs in length Results = Surgical techniques used were safe Device position within choroid = safe, and device stable for duration of the trial (2.5yrs) Possible to generate useful phosphenes Participants results = able to navigate doorways/obstacle course, and locate objects on a table In controlled environment Limitations: 1. Lab setting only, not portable 2. Small field of view 3. only 20 stimulating electrodes Ayton et al, Plos One, 2014

44 Channel Fully Implantable Study 24Ch preclinical implant 44Ch preclinical implant 24ch results and participant feedback lead to design of 2nd gen device, 44Ch fully implantable device. Name suggests device designed with more electrodes (44) – enabled wide view. Fully implantable = no exposure, fully implanted under skin, portable. Image: 24ch implant and 44ch implant (preclinical). Look similar but electrodes of the 44ch cover a larger area – hence wide view. Researchers were able to double electrodes without increasing the size of the implant. The hope of our bionic eye - Used in conjunction with participants current aids/guides and will assist in navigation and object identification eg. Identify overhanding trees, thin poles, doorways - Hope device portability will enable px to learn to use the bionic eye at home and allow them to be more independent in their normal day to day activities This trial has been registered and is up on the clinical trials.gov website and we are currently recruiting by invitation only http://clinicaltrials.gov 44 Channel Fully Implantable Study

AMD Bionic Eye Implants Currently our team not doing research with bionic eyes for AMD Group – Manchester UK running a trial with the Second Sight Argus 2 device for advance AMD. Group – French research group called Pixium were given approval last year to begin an AMD study with their AMD retinal implant called the Prima Implant Main difference = smaller than RP bionic eye implants (Prima = 2x2mm) = less retinal stimulation needed in AMD patients – less area of retina affected, localised to the macula however they are implanting into a retina that is still functioning which is a reason why our group has not entered this field Bionic eye research is developing and we are making progress. Have a long way to go before any real break through to provide patients with vision better than they already have and enable them to get rid of their visual aids all together. We do hope our research will eventually provide patients with an alternative to treatment in the future if we have not cured RP and AMD by the time bionic eyes can reliably restore useful vision. Image Courtesy: Pixium Vision

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