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Darn Near Magic: Curing Blindness with
Darn Darn Near Near Magic Magic
Curing Blindness with Implants and Chemically
Induced Cells by Sam McCommon
This old cowboy’s on the lookout for the day there ain’t no more blindness.
Curing blindness with technology has been the stuff of science fiction for decades — and even in science fiction it’s come a long way. Compare the early 1990’s depiction of Geordi La Forge on Star Trek: The Next Generation wearing a clunky visor to later iterations of the character with prosthetic implants, and you’ll see that even science fiction writers have to get more sophisticated with their imaginary technology.
If you’re not a “Trekkie” or science fiction fan, fear not: That analogy won’t go any further. We’re much more in the Wild West era of “curing” blindness, though significant steps are indeed being made to bring science fiction to life. Here, we’ll be focusing on two different treatments for retinitis pigmentosa (RP), both of which sound futuristic enough to make even the most grizzled and worldweary cowboy give them a long, hard squint and a grunt of approval. That both developments have both been published in Nature means they’re no joke: Observers would do well to keep their eyes on these projects for developments.
Artificial vision via implant
Researchers based in Lausanne, Switzerland¹ have been developing a system that combines retinal implants with smart glasses that sport a camera and a miniature computer. This system would give blind people what’s essentially artificial vision. The team is led by Diego Ghezzi, holder of the Medtronic chair in neuroengineering at the Laboratory of Neural Engineering at the Ecole Polytechnique Fédérale de Lausanne.
For now, the system is still in its early stages, though the team has been working on it since 2015. But its implications are potentially huge, and it represents a major step toward letting the blind see.
First, we need to establish a bit of background. Retinal implants for the blind currently exist, most notably the Argus® II (Second Sight, Sylmar, California, USA). However, current implants provide limited quality of life impact for patients for a few reasons. Indeed, a full third of those implanted
with Argus® II noted that it had a neutral effect on their quality of life after three years. Furthermore, most retinal implant patients stop using their implants within one to three years after their surgery. Now, as the researchers note, the currently existing technology is astounding and represents leaps over what was available previously. So what gives?
A few things, really. First, these implants provide a limited field of vision — at best 20 degrees. As the Swiss research team’s paper published in Communications Materials, a subset of Nature, noted, 30 degrees of vision is the minimum to complete everyday tasks. They noted two significant problems with visual fields lower than 30 degrees.
First, there’s not enough peripheral vision to allow for independent mobility — for example, crossing the street or navigating a crowd. This lack of independence could be what leads to the lukewarm quality of life improvements. If you still can’t move around on your own, life would be frustrating.
Second, such a narrow field is mentally exhausting for patients because they have to continually scan an area while making a mental map of their surroundings. Imagine having to do that all day, every day. Sounds exhausting, indeed.
Additionally, the current technology provides low image resolution, so that while the wearers can make out shapes and see light/dark patterns far better than, say, being entirely blind, they’re not exactly seeing in high definition either. Let’s give credit where credit’s due, though: It took a long time for computer or television screens to look any good, too.
While the Swiss team’s device isn’t ready for tests, it’s showing significant promise in both mouse models and in virtual reality. Their prosthesis, dubbed POLYRETINA, embeds nearly 10,500 functionally independent photovoltaic pixels. The smart glasses would send signals to the photovoltaic pixels which would stimulate the retina to produce “dots” of light, without color for now. The theoretical visual acuity reported by the team would be 20/480, with a much broader field of vision than competitors. It’s important to note that this concept has not yet been tested on humans, nor does the team claim it’s ready to be. But if this doesn’t whet your intellectual whistle, well … you’re a tough nut to crack, friend.
On March 10, 2021, the FDA granted Orphan Drug Designation to chemically induced photoreceptor-like cells (CiPCs) for the treatment of RP. The designation was granted to CiRC Biosciences (Chicago, Illinois, USA), which can now use the designation and the government funding that will likely follow to make significant strides in combating RP.
In an April 15, 2020 publication in Nature², the team behind the treatment noted that a set of five small molecules can transform fibroblasts into rod photoreceptor-like cells. When they transplanted these photoreceptor-like cells into the subretinal space of mice, it led to “a partial restoration of the pupil reflex and visual function.”
Apparently, CiPCs and their in vivo rod cell receptors have very similar gene expressions. The chemical conversion process takes less than two weeks, though the team noted that optimization of the team’s process may lead to greater conversion efficiency. As it is, the low conversion efficiency is one of the current main impediments to utilization of the technique. Notably, in the study, 6 of 14 mice demonstrated improved pupil reflex function. That’s just less than half — but the team pointed out that a lack of cell survival during transplant may have been responsible for the lack of improvement in some mice.
This biotechnology is in its nascent stages, and with additional research and funding we can expect to at least see more of the same — if not outright breakthroughs. That a cocktail of chemicals can take fibroblasts and transform them is nothing short of extraordinary.
The possible future implications here are also enormous. If some chemicals plus a type of cell equals another type of cell, well … might that not work in other ways as well? Have we discovered a modern form of alchemy that actually works?
Yes, the “we” above is overly generous to this publication since “we” certainly didn’t figure CiPCs out. But it’s human nature to celebrate the achievements made by our species, just like sports fans celebrate when “their” team wins. And hey, if anything’s a cause for celebration, it’s curing blindness.
References:
1. Chenais NAL, Airaghi Leccardi MJI, Ghezzi D.
Photovoltaic retinal prosthesis restores highresolution responses to single-pixel stimulation in blind retinas. Commun Mater. 2021; 2: 28 2. Mahato B, Kaya KD, Fan Y, et al. Pharmacologic fibroblast reprogramming into photoreceptors restores vision. Nature. 2020; 581: 83–88.
