Researchers Test Holographic Technique for Restoring Vision

Researchers led by biomedical engineering Professor Shy Shoham of the Technion-Israel Institute of Technology are testing the power of holography to artificially stimulate cells in the eye, with hopes of developing a new strategy for bionic vision restoration.

Computer-generated holography, they say, could be used in conjunction with a technique called optogenetics, which uses gene therapy to deliver light-sensitive proteins to damaged retinal nerve cells. "The basic idea of optogenetics is to take a light-sensitive protein from another organism, typically from algae or bacteria, and insert it into a target cell, and that photosensitizes the cell," Shoham explained.

Intense pulses of light can activate nerve cells newly sensitized by this gene therapy approach. But Shoham said researchers around the world are still searching for the best way to deliver the light patterns so that the retina "sees" or responds in a nearly normal way. The plan is to someday develop a prosthetic headset or eyepiece that a person could wear to translate visual scenes into patterns of light that stimulate the genetically altered cells.

Technion researchers show how light from computer-generated holography could be used to stimulate these repaired cells in mouse retinas. The key, they say, is to use a light stimulus that is intense, precise, and can trigger activity across a variety of cells all at once. The researchers turned to holography after exploring other options, including laser deflectors and digital displays used in many portable projectors to stimulate these cells. Both methods had their drawbacks, Shoham said.