An implantable and odd-looking microtelescope from a Saratoga, Calif., device maker could be one of the next big things in treating a common form of blindness — assuming that patients are willing to endure arduous surgery in order to obtain their new bionic eyes.
Age-related macular degeneration — a progressive loss of sight related to physical changes in the central retina, also called the macula — is the leading cause of blindness among elderly Americans, now affecting more than 1.75 million people, and potentially almost three million by 2020 (PDF link). Until recently, AMD patients had little choice but to accept the steady loss of vision as their macula deteriorated.
Over the past few years, biotech companies have made some headway against the “wet” form of AMD, in which abnormal vessels in the retina leak blood and fluid that distorts vision. In particular, two drugs from Genentech, Lucentis and Avastin, appear to block the growth of those blood vessels and, for the first time, appear to improve vision in many AMD patients. (Avastin, however, isn’t approved for AMD, although at these doses it is roughly a hundred times cheaper than Lucentis. Genentech is, of course, doing all it can to keep patients on Lucentis.) Now that those drugs have been proven to work, new experimental treatments for wet AMD are everywhere — see, for instance, our coverage here, here, here, here, here, here, and here.
Not everyone responds to the existing drugs, however, and they don’t work at all in people with the “dry” form of AMD (a group that accounts for close to 90 percent of all AMD patients). Which is where a transplanted Israeli medical-device firm called VisionCare Ophthalmic Technologies and its implantable microtelescope come in.
Both forms of AMD typically first degrade “central vision” — essentially, your ability to see whatever you’ve focused your eyes on. While many AMD patients retain some peripheral vision, losing central vision in both eyes makes it all but impossible to drive, read or perform many other daily activities. That characteristic of the disease, however, is what drove Isaac Lipshitz and Yossi Gross to found VisionCare in the mid-1990s, with the goal of developing an implantable device that might restore vision even without addressing the underlying cause of AMD.
Lipshitz designed a tiny but powerful telescope that acts like a telephoto lens, essentially enlarging images by a factor of three. That, in turn, “spreads” central vision across a wider swathe of the retina, allowing healthy retinal cells to interpret images that previously would have been restricted to their damaged macular counterparts (see graphic below).
The only catch, of course, is that you have to have this microtelescope implanted in your eye, which is not a particularly easy procedure. Surgeons must essentially lift up the cornea by one edge in order to wedge the four-millimeter-long telescope underneath it. A recent study in the Archives of Ophthalmology outlined two years of surgical experience with the device, noting that the procedure frequently damaged the endothelial cells that line the outer surface of the eyeball, and in a few cases required a complete corneal transplant.
Those risks, however, may well be worth it for patients who otherwise risk permanently losing much of their sight. In a year-long clinical trial involving 217 patients who had the device implanted in one eye, 90 percent of the subjects gained the ability to see an additional two lines on an eye chart. After a year, two-thirds of the volunteers experienced a doubling in their visual acuity (equivalent to a three-line gain on the eye chart), and 25 percent gained five lines of vision. Those patients recently completed a two-year followup, and VisionCare — now headquartered in Saratoga — expects the FDA to approve the implant by the end of this year.
VisionCare had raised roughly $46 million as of Jan. 2005, according to this VentureWire story (subscription required). The company is backed by Boston Scientific and a variety of VC firms, including Onset Ventures, Pitango Venture Capital, Three Arch Partners and Infinity Venture Capital.
For more background, see this recent Scientific American article, this item at MedGadget, and this historical piece published by the nonprofit Israel21C.