Visual Implants and Prosthesis: Interview with Brian Mech, PhD, MBA
Douglas L. Beck speaks with Dr. Mech, vice president of business development, of Second Sight Medical Products Inc., about an update on visual implants and prosthesis, outcomes, new developments, and more.
Academy: Good Morning, Brian. It's hard to believe it's been three years since the last interview!
Mech: Indeed and so much has happened since that time!
Academy: I just saw the press release announcing the European approval—congratulations!
Mech: Thanks. We're very pleased. We've been issued the "CE" mark in Europe, which allows us to initiate commercial sales in the European Economic Area (EEA) and that should start sometime in the summer of 2011.
Academy: And the CE-approved product is the Argus II retinal prosthesis?
Mech: Exactly right. We'll place the animation at the end of this interview so the readers can click in and get a better idea as to how all of these things come together to provide visual images to appropriate candidates.
Academy: Thanks, Brian. Okay, and for audiologists like me—who have very limited knowledge about things related to eye disease and ophthalmic disorders—please review for me, who are the candidates are for the Argus II?
Mech: Sure thing. The pool of potential patients for this device would be people with severe to profound outer-retinal degeneration, and across the clinical trials that included primarily people with retinitis pigmentosa (RP).
Academy: And historically, there have been no treatment protocols for these people once the retina has been damaged?
Mech: Exactly. Until now, there have been no approved treatments. RP is actually a group of genetic diseases, each with its own progression, but typically onset of vision loss begins in the 20s and proceeds until the person is functionally or even totally blind. The good news is that there are other therapies in development to address the disease earlier in the progession. The Argus II is really targeted at advanced disease.
Academy: And these are generally adult patients who had normal vision throughout their early years and so their experience includes normal occipital lobe and brain development, as RP usually occurs after reaching adulthood?
Mech: Yes, their brains have learned to use visual cues and so they are more or less "wired" to interpret visual images cognitively, so the Argus II is intended for people with advanced retinal diseases such as RP.
Academy: Please briefly describe the device?
Mech: The Argus II uses a very tiny camera mounted in a pair of special glasses to capture the visual images. The visual images are processed into electrical pulses and sent wirelessly to an electrode array surgically located on the retina. The remaining and intact cells within the retina are therefore stimulated electrically and they transmit bioelectric information via the optic nerve to the brain.
Academy: Amazing. How many patients were in the trial?
Mech: We had 30 patients in the clinical trial, and they used the Argus II in the clinic, but more importantly at home in their daily lives.
Academy: And although each patient likely had a unique visual perception, what can you tell me about a typical visual perception through the Argus II?
Mech: As you said, the range of results is large. Of course, none of them had what you or I would consider to be "normal vision" and we must keep in mind these are people who start off blind. In fact, without the Argus II, if you were to shine a very bright toward their eyes, some of them might identify that there is a light, but would not know where it was located. Using the Argus II, however, the majority of the patients could identify large letters of several centimeters in height, and many could locate visual images in space—so they could see a doorway, a chair, a wall, etc., but the most impressive results were from a few patients who could read short large print words and sentences.
Academy: Brian, to date, has anyone been implanted with bilateral devices?
Mech: No, not at this time. The field is progressing very much in parallel to how things progressed with cochlear implants. First we want to work on safety and efficacy and getting the appropriate approvals, and then I can certainly imagine significant improvements in perception through bilateral stimulation.
Academy: Yes…I can imagine that with bilateral visual stimulation the patients would be able to get some depth perception, which I presume is not possible via unilateral visual stimulation?
Mech: Yes, that's correct. I anticipate bilateral devices would allow 3D images, and you're right, at this time with unilateral stimulation, maximal depth perception isn't really possible.
Academy: Were all the patients in the trial able to perceive some visual information?
Mech: Yes, each patient was able to detect visual information through the Argus II.
Academy: And perhaps what's key here is that success is not just measured on the Snellen eye chart, but in the ability to ambulate freely without bumping into walls and furniture, and better navigating their way through their environments and by knowing things near them are moving or are stationary—all of this visual information is of enormous importance.
Mech: Exactly—there's a vast array of visual perception between normal vision and blindness, and we want to maximize the visual perception for each person with the tools we have and to the limits of our collective abilities.
Academy: Brian…this technology is amazing. Your team is to be congratulated for this pioneering work and dedication to task.
Mech: Thanks, Doug. I appreciate that. It's been a long but rewarding journey. And it isn't over yet!
Reference and Recommended Reading
Brian Mech, PhD, MBA, is vice president of business development, Second Sight Medical Products Inc.
Douglas L. Beck, AuD, Board Certified in Audiology, is the Web content editor for the American Academy of Audiology.