José-Alain Sahel holding the PRIMA implant. Picture Credit: UPMC.
According to new clinical findings released on Monday, a wireless retinal implant has shown remarkable promise in restoring central vision in people with advanced age-related macular degeneration (AMD).
Advanced atrophic AMD, also known as geographic atrophy (GA), is the primary cause of permanent vision loss among older adults, affecting more than five million people around the globe.
The study was jointly conducted by University College London, the University of Pittsburgh, and Stanford Medicine. It found that 27 out of 32 volunteers were able to read again one year after receiving the implant.
Known as PRIMA, the device is the first visual prosthesis capable of restoring functional sight to patients with irreversible vision loss. It enables them to recognise shapes and outlines, a capability referred to as ‘form vision’.
Professor José-Alain Sahel, who leads the Department of Ophthalmology at the University of Pittsburgh’s School of Medicine, stated, “It’s the first time that any attempt at vision restoration has achieved such results in a large number of patients.”
“More than 80 per cent of the patients were able to read letters and words, and some of them are reading pages in a book,” he added.
Published in the New England Journal of Medicine, the research showed that 81 per cent of patients experienced a meaningful improvement in visual sharpness. Additionally, 84 per cent reported using their prosthetic vision in daily life for tasks such as reading words or numbers.
Participants using the device showed an average improvement of 25 letters, nearly five lines, on a standard eye chart. More than 80 per cent experienced a vision gain of at least 10 letters.
AMD progressively destroys the light-sensitive cells in the retina’s centre, making detailed vision increasingly difficult.
In healthy eyes, these cells convert light into electrical impulses that are transmitted through the optic nerve to the brain.
The PRIMA system uses a 2×2 mm wireless implant to replace damaged cells. It converts light into electrical signals that stimulate the remaining healthy retinal cells.
A miniature camera mounted on smart glasses captures visual scenes. It then transmits them to the implant using invisible near-infrared light.
The implant then turns that light into electrical pulses, restoring the flow of visual information to the brain.
Users can, however, adjust zoom and contrast to optimise what they see.
After twelve months, all procedure-related side effects had resolved, and most participants showed substantial improvement in their ability to read.
One patient achieved an extraordinary gain of 59 letters,v equivalent to twelve lines, on the eye chart.
Researchers say the findings signal a major leap forward in the field of prosthetic vision. They offer new hope for people living with severe retinal degeneration.
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