In a ray of hope for the blind, researchers have used electrical stimulation of retinal cells in lab tests to produce the same patterns of activity that occur when the retina sees a moving object.
This is a major step toward restoring natural, high-fidelity vision to blind people. The first artificial or bionic vision technology is already out in the market in the US and western Europe.
This has allowed people suffering from retinitis pigmentosa to regain eyesight. However, the technology does not enable people to drive, jog down the street or see a loved one's face.
Now, a Stanford University (California) team is working to improve the technology by targeting specific cells in the retina - the neural tissue at the back of the eye that converts light into electrical activity.
"We have found that we can reproduce natural patterns of activity in the retina with exquisite precision," said E.J. Chichilnisky, a professor of neurosurgery at Stanford's School of Medicine and Hansen Experimental Physics Laboratory.
The team focused their efforts on a type of retinal ganglion cell called parasol cells. These cells are known to be important for detecting movement and its direction and speed, within a visual scene.
When a moving object passes through visual space, the cells are activated in waves across the retina.
"It is very exciting for someone who may not have seen anything for 20-30 years. It is a big deal. On the other hand, it is a long way from natural vision," Chichilnisky added. The study has been published in the journal Neuron.
