Healthcare (Commonwealth Union) – After getting treatment with an electronic retinal implant used together with augmented-reality spectacles, individuals with severe vision loss were able to regain the ability to read, according to a study led by a researcher from the University College London (UCL) and Moorfields Eye Hospital.
Data from the European clinical trial, published in The New England Journal of Medicine, revealed that 84% of participants could once again identify letters, numbers and words using artificial vision in an eye that had previously gone completely blind due to geographic atrophy caused by dry age-related macular degeneration — an otherwise untreatable, progressive eye disease.
After receiving the implant, patients were also able to read on average five lines on a standard eye test chart — whereas several of them had been unable even to perceive the chart at all before surgery.
The study involved 38 volunteers across 17 medical centres in five different nations and assessed an innovative retinal prosthesis known as PRIMA. Moorfields Eye Hospital acted as the only UK centre in the trial. All volunteers had total vision loss in the implanted eye prior to the procedure.
Dry age-related macular degeneration (AMD) involves the gradual decline of macular cells over many years, as the light-sensing cells of the retina slowly die. Most people with the dry form notice only a mild reduction in their central vision. However, through a mechanism called geographic atrophy (GA), the disease can advance to complete central vision loss as more cells die and the macula at the centre of the retina essentially wastes away. There is currently no available therapy for GA, which affects about 5 million people worldwide. Everyone who took part in this clinical trial had already lost central vision in the tested eye and retained only some peripheral sight.
This groundbreaking implant is the first device ever shown to allow individuals to read letters, numbers and words using an eye that had previously gone blind.
Mr Mahi Muqit, an associate professor at the UCL Institute of Ophthalmology and senior vitreoretinal surgeon at Moorfields Eye Hospital, who led the UK part of the study, indicated that in the timeline of artificial vision, this is a major turning point. For the first time, people who were blind are able to regain useful central vision. Nothing like this has been accomplished before.
“Getting back the ability to read is a major improvement in their quality of life, lifts their mood and helps to restore their confidence and independence. The PRIMA chip operation can safely be performed by any trained vitreoretinal surgeon in under two hours – that is key for allowing all blind patients to have access to this new medical therapy for GA in dry AMD.”
The operation starts with a vitrectomy — the gel inside the eye, between the lens and the retina, is cleared out. The surgeon then places an ultra-thin electronic implant, roughly the size and shape of a SIM card (2mm x 2mm), underneath the centre of the retina. To do this, a small “trapdoor” is created in the tissue and the chip is slid into place. After surgery, the patient wears augmented-reality spectacles fitted with a camera linked to a pocket-sized computer with a zoom function, worn on the belt.
About four weeks later, once the eye has recovered, the implant is switched on. The glasses’ camera captures the surroundings and beams the image in infrared light onto the microchip. AI software in the external computer interprets the feed and converts it into electrical impulses. These impulses are transmitted through the retinal and optic nerve pathways to the brain, where they are experienced as vision. To read text, the wearer moves and focuses the glasses over words and can magnify them using the zoom control. Patients then undergo several months of intensive visual rehabilitation to learn how to understand the artificial signals and regain reading ability.
Importantly, trial participants did not show any meaningful loss of their remaining side vision.
The results support moving forward with regulatory approval to bring this technology to market.
