Elon Musk recently that Blindsight, a cortical implant to restore vision, would have low resolution at first “but may ultimately exceed normal human vision.”

That pronouncement is unrealistic at best, according to new research from the 91̽��.

, lead author and 91̽��professor of psychology, said Musk’s projection for the latest project rests on the flawed premise that implanting millions of tiny electrodes into the visual cortex, the region of the brain that processes information received from the eye, will result in high-resolution vision.

For the study, , the researchers created a computational model that simulates the experience of a wide range of human cortical studies, including an extremely high-resolution implant like Blindsight. One simulation shows that a movie of a cat at a resolution of 45,000 pixels is crystal-clear, but a movie simulating the experience of a patient with 45,000 electrodes implanted in the visual cortex would perceive the cat as blurry and barely recognizable.

That’s because a single electrode doesn’t represent a pixel, Fine said, but instead stimulates, at best, a single neuron.

On a computer screen, pixels are tiny ‘dots.’ But that’s not the case in the visual cortex. Instead, each neuron tells the brain about images within a small region of space called the “receptive field,” and the receptive fields of neurons overlap. This means that a single spot of light stimulates a complex pool of neurons. Image sharpness is determined not by the size or number of individual electrodes, but the way information is represented by thousands of neurons in the brain.

“Engineers often think of electrodes as producing pixels,” Fine said, “but that is simply not how biology works. We hope that our simulations based on a simple model of the visual system can give insight into how these implants are going to perform. These simulations are very different from the intuition an engineer might have if they are thinking in terms of a pixels on a computer screen.”

The researchers’ approach was to use a wide range of animal and human data to generate computational “virtual patients” that show, for the first time, how human electrical stimulation in the visual cortex might be experienced. Even blurry vision would be a life-changing breakthrough for many people, Fine said, but these simulations — which represent the likely best-case scenario for visual implants — suggest that caution is appropriate.

While Fine said Musk is making important strides in the engineering challenge of visual implants, a big obstacle remains: Once the electrodes are implanted and stimulating single cells, you still need to recreate a neural code — a complex pattern of firing over many thousands of cells — that creates good vision.

“Even to get to typical human vision, you would not only have to align an electrode to each cell in the visual cortex, but you’d also have to stimulate it with the appropriate code,” Fine said. “That is incredibly complicated because each individual cell has its own code. You can’t stimulate 44,000 cells in a blind person and say, ‘Draw what you see when I stimulate this cell.’ It would literally take years to map out every single cell.”

So far, Fine said scientists have no idea of how to find the correct neural code in a blind individual.

“Somebody might one day have a conceptual breakthrough that gives us that Rosetta Stone,” Fine said. “It’s also possible that there can be some plasticity where people can learn to make better use of an incorrect code. But my own research and that of others shows that there’s currently no evidence that people have massive abilities to adapt to an incorrect code.”

Without that sort of development, the vision provided by Blindsight and similar projects will remain fuzzy and imperfect — no matter how sophisticated the electronic technology.

For now, the models developed in the study could be used by researchers and companies to aid in the placement of existing devices and the development of new technology, among other benefits. Entities like the Food and Drug Administration and Medicare could also gain insight into what sort of tests are important when evaluating devices. Further, the models provide realistic expectations for surgeons, patients and their families.

“Many people become blind late in life,” Fine said. “When you’re 70 years old, learning the new skills required to thrive as a blind individual is very difficult. There are high rates of depression. There can be desperation to regain sight. Blindness doesn’t make people vulnerable, but becoming blind late in life can make some people vulnerable. So, when Elon Musk says things like, ‘This is going to better than human vision,’ that is a dangerous thing to say.”

, 91̽��professor of psychology, was a co-author. The research was funded by the National Institutes of Health.

For more information, contact Fine at ionefine@uw.edu.

May, then of California and blind since an accident at age 3, had his sight restored through a stem-cell procedure in 2000. But what he could see afterward remained limited — colors, motion and some shapes. That prompted 91̽�� researchers to study what happened to May, and to learn more about how vision develops and how the brain responds when vision returns. The result was a in 2015 that described the visual processing skills, such as of objects and faces, that were acutely impacted during a key stage of their development.

Now May, along with 91̽��psychology professor , will speak about their experiences at 7:30 p.m. Wednesday, April 5, at Kane Hall.

The event, “Seeing the World through New Eyes: Sight Restoration from the Perspective of a Scientist and a Patient,” is part of the 12^th annual Allen L. Edwards Psychology Lectures series.

Boynton will discuss his research into “virtual patients” that simulate restored vision, while May — who worked at the CIA and has had a career in business — will talk about his efforts to see.

Register for the free lecture .

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A new 91̽�� study seeks to answer that question and offers visual simulations of what someone with restored vision might see. The study concludes that while important advancements have been made in the field, the vision provided by sight recovery technologies may be very different from what scientists and patients had previously assumed.

In a  published Aug. 3 in the journal Philosophical Transactions B, 91̽��researchers used simulations to create that mimic what vision would be like after two different types of sight recovery therapies.

Lead author , a 91̽��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.’”

Fine said the paper aims to provide information about the quality of vision people can expect if they undergo sight restoration surgery, an invasive and costly procedure.

“This is a really difficult decision to make,” she said. “These devices involve long surgeries, and they don’t restore anything close to normal vision. The more information patients have, the better.”

More than 20 million Americans aged 18 and older have experienced vision loss, according to the , and rates of vision loss are expected to double by 2030 as the nation’s population ages.

For many of these patients, vision loss occurs after light enters the eye and lands on the retina, a thin layer at the back of the eye that contains millions of nerve cells. Among those are cells called rods and cones, which convert light into electrical impulses that are transmitted to vision centers in the brain. Loss of rods and cones is the primary cause of vision loss in diseases such as or .

But those diseases leave most remaining neurons within the retina relatively intact, and various technologies under development aim to restore vision by targeting the surviving cells.

This is a pivotal time for the industry, Fine said, with one company that has a device on the market and several others set 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 the devices have a major shortcoming, co-author said, since stimulating the surviving cells in a retina is unlikely to produce vision that is close to normal.

“The retina contains a vast diversity of cells that carry distinct visual information and respond differently to visual input,” said Boynton, a 91̽��psychology professor.

“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 said. “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,” he said.

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.

Previous simulations of restored vision have used a “scoreboard model,” a grid of dots similar to the scoreboard at a football game, in which each electrode produces a visible dot in space. Together, that collection of dots is intended to demonstrate what someone with restored vision will see.

Fine said the new simulations show that the scoreboard model, which is sometimes used to test devices, doesn’t provide a good representation of the quality of vision sight restoration technologies are likely to produce. More realistic models are needed, she said, to give patients, clinicians and researchers a better idea of how those technologies will work in the real world.

Fine said better simulations can provide valuable information about how implants need to be improved to produce more natural vision.

“As these devices start being implanted in people, we can compare different types of devices and the different perceptual outcomes of each,” she said. “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.”