Fifteen years ago, I began to lose my central visual field, as a result of damage caused to my optic nerves during the early stages of multiple sclerosis.
This impairment, which by next year I could be sharing with 196 million people worldwide who could be affected by macular disease, including age-related macular degeneration, is a cruel robbery. Although basic navigational sight often remains intact, it can make it impossible to recognise the face of a loved one from a few feet away, or read the text in a book. My effective distance vision has vanished entirely. A central blind spot makes looking down a street, or even across a large room, feel like staring into a gaping abyss.
This may be about to change with the emergence of a new breed of wearable visual prosthetics aimed at enhancing real-life scenes and, perhaps most crucially, allowing people to see others’ faces.
The headsets immerse the user in a high-resolution, ultra-realistic rendition of what they are looking at, magnifying the missing part of their vision.
I recently had the opportunity to try out such a device, called the IrisVision, and was able to do things I hadn’t done in 15 years, like watching TV from the other side of the room, going to the theatre and a live football match.
The adjustable magnification meant that even sitting a few rows back, I was able to zoom in on the actor’s faces at the theatre and the crunching tackles at the football, just like I once could.
‘Wearables are now making a lot more tasks possible that were extremely difficult for us to address before,’ says Dr Michael Crossland, an optometrist at Moorfields Eye Hospital in London. ‘They are particularly useful for hands-free activities, tasks involving prolonged viewing over distance and more detailed near-vision hobbies, such as art, playing cards or reading music.’
The software allows the scene on the display to be customised for a range of visual impairments: for example, in the case of tunnel vision, the image can be shrunk down, deploying so-called ‘minification’ to match the patient’s reduced field of view, while in strabismus, often referred to as cross-eyedness, images can be shifted laterally to compensate for ‘eccentric’ eye movements.
Dr Frank Werblin is the inventor of the IrisVision and a professor of neuroscience at the University of California, Berkeley. His life’s work has focused on devising a non-invasive sight enhancement prosthetic for patients with low vision. ‘What has always been missing from the equation,’ he explains, ‘is social contact. People have been helped to use a computer and read books but they haven’t been able to see people properly. With a reading enhancement device, you can’t see across a room and you can’t recognise faces.’
Studies are examining whether this effect on social interaction may mean the device could postpone dementia among people with low vision.
What makes the IrisVision – pounds 2,895 (about Dh13,260) to buy in the UK – particularly exciting is its novel use of mainstream hardware, in the form of high-end Samsung Galaxy smartphones and the complimentary Samsung Gear VR headset.
Indeed, the arrival of the smartphone – and mass production of high performance cameras, displays and graphics processing units – has undoubtedly provided the largest technological impetus for wearable visual prosthetics.
Just as high-tensile strength carbon fibre, developed in the Fifties for transportation and heavy industry, eventually revolutionised prosthetic limbs for amputees, smartphones could now be the equivalent game-changer for low vision rehabilitation.
Currently, the two most obvious drawbacks of prosthetics like Dr Werblin’s relate to mobility and appearance. ‘The problem with an immersive device is that in boosting their central vision, the wearer loses peripheral vision essential for navigation and having a sense of where you are looking,’ says Dr Crossland.
‘If you are in a completely enclosed environment, you can’t really walk around and mobilise effectively. The challenge, in the future, will be to have something that someone can walk around in, without obstructing their visual field.’
Artificial intelligence will also likely play a role in future products, says Dr Stephen Hicks, a neuroscientist at Oxford University and a founder of OxSight, a private enterprise developing slimline eyewear for patients with tunnel vision. ‘What is vital is that the person feels like they are ultimately in control,’ he says.
The Daily Telegraph