Eye implants and high-tech glasses restore vision lost with age

People with severe vision loss have been able to read again, thanks to a tiny wireless chip implanted in their eyes and a pair of high-tech glasses.

Age-related macular degeneration (AMD) is a common condition that affects the middle part of a person’s vision, and often gets worse over time. Its exact cause is unknown, but it occurs when photoreceptor cells and neurons in the center of the retina are damaged, making it difficult to recognize faces or read. Approved treatments can only slow its progression.

The advanced stage of AMD is known as geographic atrophy, but even here, people usually retain some of the photoreceptor cells that allow peripheral vision and enough neurons in the retina to pass visual information to the brain.

And take advantage of this, Daniel Palanker He and his colleagues at Stanford University in California developed a device called Prima. It involves a small camera mounted on a pair of glasses that takes images, then projects them via infrared light to a 2 x 2 mm solar-powered wireless chip implanted at the back of the eye.

The chip then converts the image information into an electrical signal that neurons in the retina can pass to the brain. Infrared radiation is used because we cannot see at this wavelength, so the process does not interfere with any existing vision. “This means patients can use synthetic and peripheral vision simultaneously,” Palanker says.

To test this, the researchers recruited 32 people aged 60 or older with geographic atrophy. Their vision in at least one eye was worse than 20/320, meaning they could only see 20 feet (6 m) further away than someone with 20/20 vision could see at 320 feet (97.5 m).

The researchers first implanted the chip in a participant’s eyes, and then after four to five weeks, the volunteers began using the glasses in their daily lives. The glasses allowed them to magnify what they saw by up to 12 times and adjust brightness and contrast.

A year later, 27 participants were able to read again, as well as perceive shapes and patterns. They could also see five more lines, on average, on a standard eye test chart, compared to what they could make out at the beginning of the study. Some can even read with the equivalent of 20/42 vision.

“When you watch them start to read the letters and then the words, you feel a growing joy on both sides,” says one team member. “I remember one patient telling me: ‘I thought my eyes were dead and now they are alive again.’” Jose Alan Sahel At the University of Pittsburgh School of Medicine in Pennsylvania.

There is evidence that stem cell transplantation or Gene therapy It could help restore vision lost due to AMD, but these are still in early experimental stages. By giving trial participants the ability to perceive shapes and patterns, Prima represents the first prosthetic eye to restore functional vision in people with this condition.

About two-thirds of the volunteers experienced short-term side effects as a result of the transplant, including increased pressure in the eye, but this did not prevent improved vision.

“This is an exciting and important study,” he says. Francesca Cordero At Imperial College London. “It gives hope of providing vision to patients for whom this was more science fiction than reality.”

The enhanced vision that participants experienced was in black and white. “Our next goal is to add software that will help resolve gray scales and improve them for face recognition,” says Palanker. However, researchers do not expect color vision to be available any time soon.

Palanker also plans to boost PRIMA’s resolution, which is limited by the size of pixels which affects how many can fit on the chip. A more advanced version has been tested in mice. “This will correspond to people’s 20/80 visual acuity, and with electronic magnification, we can get to 20/20,” he says.

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