The short answer to whether the blind can fully regain sight artificially is no. If we are talking about sci-fi-level high-tech ocular implants, we’re still several decades away from a working prototype. That being said, the last few decades have been quite promising in two ways. The first is further refinement of earlier concepts, and the second is the continued improvement of already implemented rudimentary light transduction designs.
So while it may not be the multi-purpose bionic eyes Geordi La Forge wears in Star Trek, these achievement milestones have at least become part of the journey to eventually get us there.
What is a Bionic Eye?
Bionic eyes are prosthetic implants that try to replicate visual phototransduction, which is the natural process our visual system (brain + eye connection) uses to convert light into electric signals. Because of how vastly complex the process of natural eyes is, bionic eyes are currently incapable of a perfect recreation. Instead, the artificial component compensates by simply processing light in some rudimentary manner so the brain can process it.
For example, a photosensitive microprocessor can be implanted behind the retina, which would act as the rods and cones of the eyes. The information is then transmitted wirelessly to a wearable device, which would transmit the information to the brain as simple luminous flashes.
Based on current bionic eye implants, there are two primary methods of achieving this function, namely:
1. Transducing light intensity only, “lights in lights out”
This is the simplest method of providing rudimentary eyesight, and is technically the very first type of eye that was developed millions of years ago on Earth. As the name suggests, the only information gathered and sent to the brain is how bright or dull the light is within the bionic eye’s sight range. No other details are provided whatsoever, although movement can perhaps be detected by determining patterns in light signals as they actively change.
The concept may sound useless, but it means an otherwise blind person means can immediately assess potential obstacles or at least determine the type and layout of the room they are in. Combined with other sensory information, and other assistive tools, the bionic eye wearer should theoretically be able to navigate much more efficiently.
There is no strict requirement to how this is achieved, so long as there is a method for the system to collect light signals and process them in a way that the information can be sent directly to the brain.
2. Recognising shapes and shadows, “mono pixelated vision”
A step up from simply measuring ambient brightness, certain bionic eyes can also provide information that could allow users to see rudimentary patterns and shapes around them. Colors remain largely black and white, although this time users can see “low resolution” images of what we would normally see. Again, this bionic eye is built in a way that replicates natural retinal processes, but instead uses an external optical device to allow the brain to physically make out the images.
It is perhaps no wonder that this type of artificial sight system is much better, simply due to the higher level of detail. The image discerning function of the eyes is basically restored, albeit at a significantly impaired level. Think of a near-sighted person losing their glasses and trying to navigate around, only multiply that sensation by tens of times. They won’t immediately fumble around the smallest bump, but it would still be very much difficult for them to accurately differentiate everything around them.
What is the Most Advanced Bionic Eye in the World?
In terms of theoretical design, the most advanced bionic eye currently in development (as of this article’s writing) is Second Sight’s upcoming Orion neural implant. Instead of artificially restoring the function of the retina, a custom camera is hardwired into a system that allows it to send the image information directly to the brain. The electrode array implanted in the brain’s visual cortex acts as the translator, sending pulses of electric signals that convert the visual data.
Orion is not currently approved as a medical product, and is still in the experimental stage. The array only has 60-electrodes prior to evaluation, which directly translates to about being able to convert signals to a 60-pixel image… not exactly the resolution you want for a crisp and clear image. As of late 2020, only six test subjects have experienced using the prototype.
As for the most advanced bionic eye already in practical use right now, that would have to be the Argus II Retinal Prosthesis System, again a product developed by Second Sight. Aimed specifically at patients with retinitis pigmentosa, it provides the aforementioned “mono pixelated vision” by implanting a sensor into the damaged retina, and uses the rest of the hopefully-still-intact visual system (the pupils, especially) to keep conveying simplified light signals to the brain.
Unfortunately, this marvelous technology is now facing its support lifetime issues ever since Second Sight started a complete focus shift towards Orion. And as of 2019, official approval to use the Argus II system for new patients is closed.
Challenges, Hurdles, and Issues of Bionic Eyes
As with any branch of advanced bionics, most of the problems related to bionic eye development are related to implementation, which either refers to its level or scope:
High-level vision restoration is still impossible – perfectly restoring image clarity to the processed visual information of current bionic eye implants is currently not an option. The natural retina is still vastly more complicated than any sensor or electrode array built to replace them.
Only works for certain diseases – if you suffered from any medical emergency that caused your eyeballs to be removed entirely, then you’re out of luck. Many bionic eye services can only provide the technology if the eyeball itself is still somehow intact, and its pupil can still properly take in light. Technologies that aim to bypass this limitation, such as the Orion neural implant, are still currently in development.
Very limited availability – there is a reason why we still haven’t seen bionic eye technology become available at the industrial scale as regular bionic limbs. If you don’t have access to a particular medical institution or academic center that specializes in them, then no bionic eyes for you.
Highly impractical costs – and yes, because the economies of scale can’t work on bionic eye research, the costs of availing them are exorbitantly expensive. It’s typically more than $100,000 for the implant alone, excluding additional hardware and medical procedures.
Rapid obsolescence (limited service support) – with rapid advancements to sensor technology every few years, most sensors and optical systems used for current bionic eyes can potentially become obsolete in as little as a decade. As mentioned earlier, this problem was made apparent with the announcement that Second Sight will soon stop active support of the Argus II bionic eyes.
Can’t We Just Connect HD Cameras to the Brain?
The tricky thing about our highly-detailed 4K cameras mounted on our phones today is that they are optimized to send the signals to a binary processor. The processer is then wired to translate the data onto a physical medium that represents visual pixels, before we ourselves can see the image directly.
We just can’t accurately process that level of data into something we could directly send to the brain at our current level of technology. With further development in the next few decades, maybe. But for now, a few massive hurdles in the field of brain-machine interfaces have to be tackled before we can do anything about this.
This makes it somewhat understandable, even if still quite ruthless, why Second Sight abandoned its previous product in favor of brain implant development through Orion.
Featured image credit by Stefan Insam via Flickr.