These High-Tech Glasses and an Eye Implant Restored Sight in People With Severe Vision Loss

Globally, more than five million people are affected by age-related macular degeneration, which can make reading, driving, and the recognition of faces impossible. A new wireless retinal implant has now restored functional sight to patients in advanced stages of the disease.

The condition gradually destroys the light-sensitive photoreceptors at the center of the retina, leaving people with only blurred peripheral vision. While researcher are investigating whether stem cell implants or gene therapy could help restore sight in these patients, these approaches are still only experimental.

Now though, a system called PRIMA built by neurotechnology startup Science Corporation is helping patients regain the ability to read books, food labels, and subway signs. The system consists of a specially designed pair of glasses that uses a camera to capture images and transmit them wirelessly to a tiny chip implanted in the retina that then stimulates surviving neurons.

In a paper published in The New England Journal of Medicine, researchers showed that 27 out of 32 participants in a clinical trial of the technology had regained the ability to read a year after receiving the device.

“This study confirms that, for the first time, we can restore functional central vision in patients,” Frank Holz from the University Hospital of Bonn who was lead author on the paper said in a statement. “The implant represents a paradigm shift in treating late-stage AMD [age-related macular degeneration].”

The system works by converting images captured by the camera-equipped glasses into pulses of infrared light that are then transmitted through the patients’ pupils to a two-square-millimeter photovoltaic chip. The chip converts the light into electrical signals that are transmitted to the neurons at the back of the eye, allowing the patients to perceive the light patterns captured by the glasses. The PRIMA system also includes a zoom function that lets users magnify what they’re looking at.

Daniel Palanker at Stanford School of Medicine initially designed the technology, and a French startup called Pixium Vision was commercializing it. But facing bankruptcy, the company sold PRIMA to Science Corporation last year for €4 million ($4.7 million), according to MIT Technology Review.

Palanker said the idea for the product came 20 years ago when he realized that because the eye is transparent it’s possible to deliver information into it using light. Previous systems also relied on camera-equipped glasses to transmit signals to a retinal implant, but they were connected either by wires or radio transmitters.

In the recent study, 32 people with a form of macular degeneration that destroys photoreceptors in the center of the retina received implants in one eye. After several months of visual training, 80 per cent of them had regained the ability to read text and recognize high-contrast objects.

Some participants achieved visual acuity equivalent to 20/42 when images were zoomed. And 26 of them could read at least two extra lines on a standard eye chart, with the average closer to five lines.

Because PRIMA uses infrared light to stimulate the chip, these signals don’t interfere with the remaining healthy photoreceptors surrounding it, allowing the brain to merge the restored vision in the central region with the patients’ residual peripheral vision.

The chip is currently only capable of producing black and white images with no shades in between, which limits patients’ ability to recognize more complex objects like faces. But Palanker says he is currently developing software that will allow users to see in grayscale. The researchers are also developing a second-generation implant that will have more than 10,000 pixels, which could support close to normal levels of visual acuity.

One of the participants told the BBC that using the device requires considerable concentration, and it’s not really practical on the move. But Science Corporation told MIT Technology Review it is also in the process of slimming down the bulky glasses and control box into a sleeker headset that would be only slightly larger than a standard pair of sunglasses.

Given the huge number of people affected by macular degeneration, the market for such a device could already be large, but the designers hope the approach could also help cure other vision disorders. The company has already applied for medical approval in Europe, so it may not be long before neuroprosthetic devices become a standard treatment for those with vision loss.