Vision Quest

An ingenious new device could lead to an eye implant that restores sight to the blind.
This summer, physicist Mark Peterman and his Stanford University colleagues reported that they had constructed an artificial stand-in for photoreceptors, eye cells that register incoming light and dispatch chemical signals to relay that information to the brain. Their prototype is a one-square-
centimeter silicon chip with 50-micron-wide channels etched into its surface. When activated, an electrode attached to the chip generates an electric field that pushes fluid through one of the channels. Some of the solution drips through a tiny hole in the channel floor and mingles with a cell colony placed below the chip. By adjusting the field, Peterman can control the fluid’s flow and, in turn, the amount delivered to the cells, just as a healthy photoreceptor regulates signals sent to the brain. The team now plans to make the chip smaller and etch in thousands more channels.
If all goes according to plan, an implant could be ready for animal trials within the next few years.