What would the world look like through bionic eyes?
A new study simulates what people who have sight recovery therapies will actually see.
We can give people new hearts and limbs and joints and various implants to fix this and that, yet the ability to give people sight has been a stretch. But not for long. Companies around the world are working on different sight recovery therapies and success is near. And with more than 20 million Americans adults alone suffering from vision loss, according to the American Foundation for the Blind, it can’t come quickly enough.
But what will the world look like to people who have these procedures? Will they have superhuman vision like the six million dollar man?
A new University of Washington study set out to answer that question and arrived at visual simulations of what someone with restored vision would see. The researchers concluded that while remarkable advances have been made in the field, the actual vision that might be achieved is likely far different from that which many have imagined. Given that sight restoration surgery is an invasive and costly procedure, it seems prudent to know what to expect.
The University of Washington researchers used simulations to build short videos that mimic what vision would be like after two different types of sight recovery therapies. Lead author Ione Fine, a UW associate professor of psychology, said the simulations are unprecedented.
"This is the first visual simulation of restored sight in any realistic form," she said. "Now we can actually say, 'This is what the world might look like if you had a retinal implant.'"
This is an important time for the sight-restoration industry, Fine says; there is one company that has a device on the market and a few others that will be ready to enter the market in the next five to 10 years.
Two of the most promising devices, she said, are electric prostheses, which enable vision by stimulating surviving cells with an array of electrodes placed on the retina, and optogenetics, which insert proteins into the surviving retinal cells to make them light-sensitive.
But even though the work is promising, the devices have a major shortcoming, co-author Geoffrey Boynton says, since stimulating the surviving cells in a retina is unlikely to produce vision that is how we might expect it to be. In a word, normal.
© The black and white images show visual distortions that might result from electric prostheses that enable vision by stimulating the retina. (Photo: Ione Fine and Geoffrey Boynton/University of Washington)
"The retina contains a vast diversity of cells that carry distinct visual information and respond differently to visual input," says Boynton. "Electrically stimulating the retina excites all of these cells at the same time, which is very different from how these cells respond to real visual input."
There are similar issues with optogenetics, Boynton says. "The optogenetic proteins that are currently available produce sluggish responses over time, and they are limited in the number of different cell types that they can separately target."
These limitations in both technologies mean that patients may see fuzzy, comet-like shapes or blurred outlines, or they may experience temporary visual disappearances if an object moves too fast explains a press statement from the University.
© Limitations in sight recovery technologies can cause fast-moving objects to seemingly disappear, as shown in the above image of a child on a scooter. (Photo: Ione Fine and Geoffrey Boynton/University of Washington)
Previous simulations of restored vision have not accurately demonstrated what someone with restored vision will see, says Fine. More realistic models are needed, she offers, to give patients, clinicians and researchers a more clear idea of how those technologies will work in real time.
"As these devices start being implanted in people, we can compare different types of devices and the different perceptual outcomes of each," she says. "The path to fully restored eyesight is an elusive target. We need to start developing more sophisticated models of what people actually see.
"Until we do that, we're just shooting in the dark in trying to improve these implants."