Blindness From Eye Damage Should Have Been Consigned To A Dusty Old Box In The Attic By Now
Sight shouldn’t rest on the roll of a dice
Looking is an action of the mind
In cases where blindness is caused by damage to the eye (as opposed say to brain damage), it should be possible to restore sight using technology. It’s one of those areas where the theory was put forward a long time ago, and we have waited for the technology to catch up.
Are we there yet? I’m pretty sure we are, so why isn’t it happening? The question posed itself when I read these words in an article by Hayden Moore:
Looking is an action of the mind, whether eyes are involved, or not.
I was whisked back half a century to a time when technology was becoming routine in mainstream healthcare. My research group had been invited to join a consortium led by Compiegne University. Their underlying idea was based on the theory that sight could be restored to people with particular forms of blindness, via the development of a specialised type of action camera.
If it was left to the eye, we would see upside down
The human eye and how it works is undoubtedly a marvel, but as a camera, it is a simple and unsophisticated gadget. Light passes through the lens to produce an inverted image on the retina. The photoreceptors of the retina convert the light to electrical signals that are passed through the optic nerve to the visual cortex of the brain.
In essence, the brain receives a simple inverted image. If it was left to the eye, we would see a capsized world. That’s why small babies have trouble reaching for things — everything appears upside down until experience from their other senses teaches their brain to turn the world the right way up.
If you close one eye, you can’t judge distance… except that you can. If you don an eyepatch and go to a fancy dress party as a pirate, you won’t bump into things and fall over (unless you have too much to drink) but your one uncovered eye will be doing nothing to calculate distance. All the work of navigating objects, of deciding which is close and which is far, is being done by the stored lifetime’s experience in your brain.
A tribute to neuroscientist and visionary, Paul Bach-y-Rita
The work proposed by the team in Compiegne paid tribute to American neuroscientist and visionary, Paul Bach-y-Rita, the researcher who led the first serious studies of neuroplasticity in the mid-20th century. By the late 1960s, Bach-y-Rita had demonstrated that the light from camera images converted to vibrations on the skin allowed blind people to recognise objects coming towards them. He theorised that the vibrations were being processed in the visual cortex of the brain, though he had no means to prove that at the time. Through various experiments, he showed that lost senses could be replaced by different stimuli, and further that the body could retrain itself to accept signals from different senses for particular purposes.
We see well enough when we dream
Jumping ahead to the work we were involved in, in the late 1990s, it was proposed that when accident or illness caused damage to someone’s eyes and they went blind, it should be possible to use fairly basic technology to bypass the broken ‘camera’ of the eye and restore sight.
We already know we have the ability to see sharp and complex images without needing our eyes to be open — we see well enough when we dream.
The plan was straightforward in outline, but the devil as ever was in the detail. A camera, not unlike the currently popular GoPro, would be adapted, such that light entering it would be converted to electrical signals that would be transmitted into the body with a view to training the brain to process them within the visual cortex and turn them into sight.
The simple statement of intent hid a multitude of areas to be explored and investigated. For example, would it be possible to send stimuli directly to the optic nerve? That whole mechanism is already set up to take such signals, pass them to the visual cortex, and generate vision. Perhaps that would be all that was needed to restore sight in someone whose eyes no longer worked. On the other side of that coin, the safety implications of wearable technology sending signals into nerves in the head, are huge. The question was not only could it be done, but could it be done safely?
Or should we revisit Bach-y-Rita’s early experiments in which he showed that the brain was capable of translating vibrations in the spine — via the visual cortex — into the beginnings of sight. Perhaps all we needed to do was to capture the light and convert it to a stimulus the body could detect — and from there let the brain do the work.
It would not be a new process. We would give the brain signals replacing those it could no longer receive from damaged eyes, then train it that these signals were related to the visual world around us. This is little different from the process by which babies’ brains unravel sensory inputs, learning that touch fails to match the inverted image. A sighted person who has gone blind has a brain with a wealth of experience to draw on, a brain that knows what the world looks like. There is no reason that people with non-working eyes shouldn’t see as clearly and as accurately as sighted people.
Making sense of the senses is not straightforward
Which of many approaches would have worked best?
I wish I could answer that, but I can’t. We had the expertise in the group, but we didn’t get the funding we needed. The funding body felt that the idea was sound but the technology wasn’t yet of a standard to allow for quite such ambitious aims. In hindsight, I think they were probably right. Although people had been experimenting with helmet-mounted cameras since the 1960s, at the time we were putting this research consortium together, the first commercial helmet-mounted action camera was a decade in the future.
My research group went on to other things and I lost touch with the group pursuing Bach-y-Rita’s original goals. An experimental camera device got as far as allowing people without sight to distinguish light and shade, but it was clunky, hard to wear, and didn’t do enough to make it a generally viable proposition.
The decades of research done in this area have proven some basic concepts. The brain can and does adapt itself to the loss of some senses.
We perceive the world by integrating the information that comes from our senses. Our brains can be adaptive and integrate sensory information in many different ways. We know how senses can mix and merge from the condition of synesthesia where people might hear sounds as colours or taste words.
We have 5 basic senses — touch, sight, hearing, smell, and taste — and many more, including balance and space. We have senses we’re not consciously aware of, such as the sense that detects oxygen levels in key arteries.
The total number of senses we have does not lend itself to an easy answer — not because we haven’t found them all, but because it depends on how you define them. It wouldn’t be wrong to say there are only 3 senses if you define them by the three types of stimulus they sense — light, chemical, and mechanical — but it is also possible to list more than 20 distinct human senses. Making sense of the senses is not as straightforward as you might think.
We could restore sight to millions
Why have we not yet cured blindness in the case where the only damage is to the eye? There’s a whole body of research out there to show that sight need not be dependent on the eye being in working order. All it needs is for the light signals to arrive in the brain by some means, perhaps as electrical signals to the optic nerve, vibrations to the spine, sounds, or any one of a multitude of stimuli that the brain could learn to interpret as sight. It’s not as though technology is a barrier any longer.
The barrier now is money and motivation. Because that’s another concept that has been demonstrated over the decades. If the motivation is there for the money to be made available, we can move mountains, and move them pretty damned quickly too!
We know that diseases can be blitzed, with cures, treatments, and vaccines produced in record time. All it takes is to give the right people the time, space, and equipment to work on the problems. It irks me somewhat that resources can always be found for war, but can only be found to tackle disease and public health when a critical number of rich and influential people are affected, or if something threatens to become a global pandemic.
We have the expertise, we have the technology. We could consign blindness to a dusty old box in the attic, and restore sight to millions. If only we had the will.
