Retinal Implants and Bionic Eyes to the Rescue

By May 20, 2017 No Comments

If you went blind today, how would it affect your life? We rely on our vision for just about everything we do. Going blind means losing independence and employment, and having to give up a long list of pleasurable things. People without sight have exhibited incredible bravery in the face of a tough disability, but perhaps one day science and technology will eliminate blindness altogether. It’s an incredibly important goal to have.

There are very few statistics on blindness that aren’t estimates with a fair error margin, but according to the National Federation for the Blind there are about 665,000 blind children in the USA. Among adults there are nearly 7.4 million people who are legally blind. That’s a lot of people whose lives would completely change if they were given their sight again.

Esight Glass

Legally Speaking

You’ll also notice the term “legally blind”, which alludes to a very important fact about blindness. Most people think being blind means not having any vision at all, but there are many different degrees of blindness and they are caused by different things. This means that, just as with cancer, there is probably no universal cure for blindness. It’s a symptom of different diseases and disorders. So in this article I plan to highlight a few technological developments that can help people with varying types of blindness as well as some future developments that may one day cover just about any cause of blindness.

eSight Glasses

Because so many people who are legally blind still have some form of sight left, one strategy to help return their lives to what sighted people experience is to enhance the sight they do have. We already do it for people with poor eyesight who aren’t blind – that’s what corrective lenses do, after all. However, if your vision is 20/200 or worse there are now electronic solutions that can help. Think of them as a sort of “super glasses”.

One of the most successful examples of such a device is the eSight.

Goggly Eyes

The eSight is basically a set of video goggles with high-quality integrated optics and cameras connected to a portable visual-processing computer. The wearer can adjust what they see or how the picture is enhanced using a little control box. The eSight has improved the vision of legally-blind people from 20/200 to anything between 20/1200 and 20/20. It works for young children and the elderly and for people with very different lifestyles.

It does not, however, work for everyone, which is why the company encourages people to try a unit to see if it works for them. Some people just can’t adjust to the glasses and others have vision loss that doesn’t benefit from what the eSight does.

The biggest problem with the device is how expensive it is. You’ll need $15,000 to own one. Apart from that, it’s still a pretty large and clunky device, but improvements in the components should see it shrink down significantly over the years.
It really is a revolutionary little machine that can make all the difference in the lives of millions of people.

Check out this video of a man seeing again for the first time in 20 years, using an eSight.

Retinal Implants

Of course, there are plenty of people who have no vision because the part of their anatomy responsible for sharp vision is no longer in good enough shape. The retina is the part of the eye that’s light sensitive. It’s the equivalent of the image sensor in your camera. The rest of your eye could be completely fine in terms of the optics of it all, but you’ll still see nothing of the retina doesn’t do it’s job.

To give you an idea of what retinal defect is like, think about your blind spot. Every human being has a blind spot in their eye where no visual info goes to the brain. You don’t notice it normally because your brain sort of glosses over it. You can find it pretty easily though. Just take a piece of paper and draw an “X” on it. Draw a dot 5cm to the left of the X. The dot should be about the size of a US penny. Close your right eye and look at the X with your left. The dot will still be visible in the periphery of your vision. Now move the paper left or right and in or out while staring at the X. At some point the dot will disappear, which means you’ve found your blind spot. It exists because the optic nerve dives back through the retina, thanks to an evolutionary quirk.

By using an implantable device that sits on the retina, it may be possible to restore some vision to people that have retinal diseases.

When the Retina Goes Dark

There’s a depressingly long list of things that can go wrong with a retina. Among other things, it can detach, get infected, or just sort of wither away for various reasons. Type II diabetes is a common cause of retinopathy, for example. Or you may just take a knock to the face while playing sports. The end result is broadly the same.

Needle in the Eye

In 2015 the first recipient of an FDA-approved retinal implant successfully completed his operation. 80-year old Ray Flynn suffers from macular degeneration, an abnormality in the part of the retina that provides clear central vision. He was fitted with the Argus II retinal prosthesis, restoring a degree of the central vision that he’s lost.

The operation is a delicate one that takes a few hours. The vitreous eye jelly is removed from the eye and the membranes that cover the retina are also removed, exposing it. The tiny implant is attached to the surface of the retina with a tiny surgical tack and a little cable is run through a part of the eyeball, which will carry signal and power. That cable attaches to a signal processor which gets data wirelessly from a digital camera, mounted to a frame similar to normal glasses. The current model of this implant has 60 electrodes, each one measuring only 200 microns across. That’s about twice as thick as a strand of human hair.

Eye Lens Bionics

I Can See (Sort of) Clearly Now

With relatively few visual elements and a operating principle somewhat different from a natural retina, the vision you get from the Argus is not like normal vision. It is of benefit to people who have no light sensitivity at all. In other words, they have to do everything using senses other than vision. With a retinal implant like this people can now do things like orient themselves in a room. They can figure out where a door or window is, follow straight lines, see boundaries, or avoid walking into things. It may not seem like much, but compared to total blindness it’s almost miraculous.

Forward to the Future

More importantly, it proves the concept of retinal implants as a whole. Future models with many more electrodes and smaller components, and without a need for external parts or power, could restore normal vision. It’s now just a case of continuously refining a technology that already works.

Code Breakers

It’s not just about the hardware to interface with or replace the retina. What matters just as much, if not more, is understanding the neural code the retina uses to talk to the visual cortex of the brain. Think about it this way, if you send a signal to your TV in a format that it doesn’t understand, you’ll get either no picture or a very bad one. So figuring out what “language” the visual cortex speaks with the retina is crucial.

One scientist has pioneered the research into this area and successfully cracked the visual code with several animal models such as mice. Sheila Nirenberg has made massive strides in figuring out how to talk to the brain when the visual chain is broken. Her latest solution uses a mix of camera technology and genetic engineering to give the brain visual information. The genes she implants into the eyes respond to the coded messages from the camera and relays them to the brain, allowing for vision.

Attack of the Bionic Clones

Of course, most people would rather just have their natural eyes back instead of all sorts of technological stuff attached or implanted in them. At least for now, these prostheses don’t fully restore vision and are still cumbersome. Biotechnology is not standing still and technologies such as cloning and lab-grown organs could allow for transplants that make a blind person completely whole again. At present only parts of the human eye can be transplanted, the cornea being a prime example. Transplanting an entire eye remains a challenge, regardless of the source. Obviously a cloned eye won’t suffer from rejection issues, but attaching the optic nerve and all the fine muscles that move the eye is a huge prospect.

Nerve regeneration science is a hot area of research, since it can also help with things like spinal cord injuries. Stem cells are a main method under investigation, where cells from your own body are coaxed to become the right sort of nerve cell and bridge the gap. Perhaps in the end a neural-implant that repeats signals from one side of the gap to the other could be the answer.

Medical scientists are now very confident that one day whole eye transplants will be possible.

This would be a great option, given that the eye itself is a massively complex organ. Using a working eye or growing a new cloned organ could in fact be a simpler solution overall than implants or partial transplants – letting nature take care of all the most difficult issues.

Eye Research

Cortical Blindness

There is one type of blindness that no amount of eye-doctoring will ever cure. It’s called cortical blindness and happens when something goes wrong with the “visual computer” of your brain. The optic nerves may be sending the right signals, but the visual cortex is either dead or interprets the signals incorrectly. To cure that sort of blindness will require a technology or treatment that doesn’t yet exist. In theory it could be a brain prosthesis – an artificial machine that aids or replaces the function of a particular brain structure. Perhaps stem-cell or gene therapy hold an answer. We just don’t know yet.

Light at the End of the Tunnel

I don’t think it’s controversial to say that by the end of the 21st century most forms of blindness will be completely cured. That’s an amazing thought to have and a wonderful development to look forward to. The elderly could do more for longer and people who are otherwise healthy can become fully-productive members of society. Maybe we’ll all have eye-implants or artificial eyes at some point, just because they may be better than the ones that we have been born with. A bright future indeed.