The Bio-Retina developed by Nano Retina costs around $60,000 and is a vision-restoring sensor that is actually placed inside the eye, on top of the retina. The operation only takes 30 minutes and can be performed under local anesthetic.
Basically, with macular degeneration and diabetic retinopathy, the light-sensitive rods and cones in your retina stop working. The Bio-Retina plops a 25×23-resolution (576-pixel!) sensor right on top of your damaged retina, and 576 electrodes on the back of the sensor implant themselves into the optic nerve. An embedded image processor converts the data from each of the pixels into electrical pulses that are coded in such a way that the brain can perceive different levels of grayscale.The best bit, though, is how the the sensor is powered. The Bio-Retina system comes with a standard pair of corrective lenses that are modified so that they can fire a near-infrared laser beam through your iris to the sensor at the back of your eye. On the sensor there is a photovoltaic cell that produces up to three milliwatts — not a lot, but more than enough.
Human trials of Bio-Retina are slated to begin in 2013 — but US approval could be a long time coming. European approval is predicted to occur much earlier. Multiple research groups are working on bionic eyes with even more electrodes and much higher resolution. A lot of work is being done on understanding how the retina, optic nerve, and brain process and perceive images