Researchers work on device that could restore sight

The prosthetic retina is being designed for patients suffering from age-related macular degeneration (AMD), one of the most common causes of blindness in the developed world.

‘It’s not dissimilar to a solar cell in that light hits it and it generates an electrical signal,’ said Simon Andrews, business development manager at Strathclyde University’s Institute of Photonics.

The silicon device converts pulsed near-infrared light to electrical current that is used to stimulate neuronal cells in the retina and generate an image.

The researchers claim that it is an improvement on current solutions because it requires no wires and can be implanted with less-severe surgery compared to most prosthetic retinas that are powered through implanted coils.

Andrews explained that ‘video goggles’ would be used to deliver energy and images directly to the eye.

‘A camera [on the goggles] takes information from the outside world and electronics are used to turn that signal, or information, into an infrared laser,’ said Andrews. ‘The infrared laser would then project an image onto an array of solar cells at the back of the eye.’

The electrical stimulation is then carried by optic nerves to the brain, where it can be interpreted, allowing a patient to see.

The device has been shown to produce encouraging responses in initial lab tests on rats and is reported in an article published in Nature Photonics. The technology is now being developed further.

AMD affects one in 500 patients aged between 55 and 64, and one in eight aged over 85.

‘This is very interesting research particularly as Age-related Macular Degeneration (AMD) is the leading cause of sight loss in the UK and research indicates that there will be an increase in the number of people diagnosed with AMD over the next decade,’ said Clara Eaglen, eye health campaigns manager at the Royal National Institute of Blind People.

‘Clearly it is still at an early stage and more extensive trials are needed to confirm the safety and effectiveness of this kind of treatment, but at some point in the future prosthetic retina implants may become part of the armoury of treatments for sight-threatening eye conditions.’

The project, led by Dr Keith Mathieson, was supported through a fellowship from Scottish Optoelectronics Association (SU2P), a venture between academic institutions in Scotland and California aimed at extracting economic impact from their joint research portfolio in photonics and related technologies.

Strathclyde leads the collaboration, which also includes Stanford, the universities of St Andrews, Heriot-Watt and Glasgow, and the California Institute of Technology. SU2P was established through funding from Research Councils UK — as part of its Science Bridges awards — the Scottish Funding Council and Scottish Enterprise.