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On Tech & Vision With Dr. Cal Roberts

Mar 4, 2022

This podcast is about big ideas on how technology is making life better for people with vision loss.

The Enigma machines that Germany used to encode messages during World War II were notorious for their complexity. Two Enigma experts — Dr. Tom Perera, a retired neuroscientist, and founder of, and Dr. Mark Baldwin, an expert on the story of Enigma machines — tell us how the Allies were able to crack the code, by using input-output mapping.

The human brain is similarly complex. Until recently, no one knew the code the retina used to communicate with the brain to create sight. Our guest, Dr. Sheila Nirenberg, a neuroscientist at Weill Cornell, and Principal and Founder of Bionic Sight has — using input-output mapping — cracked the retina’s neural code, enabling her to recreate the electric signals to the brain that could restore sight in people with retinal degeneration. She has created a set of goggles that convert a camera’s images into the code, via pulses of light. And she relies on optogenetics, a relatively new procedure in neuroscience that helps neurons become responsive to light. In her clinical trial, Dr. Nirenberg injects the optogenetic vector into the eye, and trial participants who are completely blind, like Barry Honig, who we speak with on this program, report being able to see light. In early studies, coupling the effects of the optogenetics with the code-enabled goggles has an even more impressive effect on patients’ vision. Dr. Nirenberg is also using her knowledge of the visual neural code to inform machine learning applications that could also be further used to support people who are blind or visually impaired. Clinical trial participants are important partners in the journey of discovery, Dr. Nirenberg says. Barry Honig agrees. He was happy to participate to help ease the burden on future children diagnosed with eye diseases that would otherwise result in blindness, but thanks to these advancements, someday may not.


The Big Takeaways:

  • Dr. Tom Perera and Dr. Mark Baldwin describe the history and workings of the Enigma machine, the complex encoding device that allowed Germany to take the upper hand at the beginning of World War II, a war in which communication was sent wirelessly, elevating the need for encryption. They then describe the Polish and British efforts to break Enigma, including standard decryption and Alan Turing’s Bombe machine.
  • Similar to the Enigma, the human brain is incredibly complex, and much of the codes that make it run have not yet been deciphered, until now.
  • Our guest, Dr. Sheila Nirenberg, conducted extensive input-output mapping on live human retinas. She was able to keep them alive in a dish outside the body for a few hours, during which time she’d show them videos. As the retina perceived the films, Dr. Nirenberg mapped the electrical current that would pulse through the ganglion nerve. In this way, she was able to learn how the human eye sees and to decipher the code that allows our brains to perceive images. This code has been honed via evolution over millennia.
  • Having cracked the retinal neural code, Dr. Nirengberg held the key to restoring vision in people who are blind from retinal degeneration. She developed goggles embedded with a camera to convert the visual world into the retina’s neural code using pulses of light, but she still had to get these pulses of light into an unseeing eye.
  • Optogenetics is the key to creating light perception. Optogenetics is a relatively new procedure in neuroscience, by which researchers have created a genetically modified virus based on light-responsive algae, which when injected into live human cells, recombines its DNA with the DNA of host cells. In Dr. Nirenberg’s case, she injects the optogenetic vector into the patient’s retina. Most patients report the restoration of light perception to varying degrees, with just the optogenetics alone. Coupled with the goggles, and with Dr. Nirenberg’s visual neural code, this system could restore some vision in people who are blind. The trial is still in its early stages.
  • Dr. Nirenberg also uses the retinal neural code to improve how computers see. Computer vision experts are teaching computers to “see” more like humans. Still, if they can equip algorithms with humanity’s neural code, the goal of human-like vision becomes more easily achievable.
  • Barry Honig is a participant in the clinical trial. After his optogenetic injection, he was able to perceive the menorah at Hanukkah. From different perspectives, Barry and Dr. Nirenberg agree on the importance of trial participants.



  • “The analogy between the Enigma and the human brain is rather interesting. The brain has … 10 billion brain cells, … the Enigma machine has 10 to the 114th power possible internal connections. And that is actually a lot more.”
  • — Tom Perera, neuroscientist and founder of
  • “Millions of years of evolution honed the retina into pulling out … the right features. And then it converts those features into electrical pulses and sends them up to the brain. That’s what a normal retina does.”
  • — Dr. Sheila Nirenberg, neuroscientist at Weill Cornell, and Principal and Founder of Bionic Sight.
  • “And so … you’re watching the retina watch a movie. And … you’re seeing what it would be sending … to your brain.”
  • — Dr. Sheila Nirenberg, neuroscientist at Weill Cornell, and Principal and Founder of Bionic Sight.“So I went from … sort of bare light perception to … this recent past Hanukkah, I … said to my … wife, the menorah — I think it was the eighth day and … the whole menorah was lit!”
  • — Barry Honig, clinical trial participant and founder of Honig International
  • “Whether or not that’s perfect, you know, time will tell, but … to be able to spare kids that, and equally as importantly, to spare their parents that, you know, if I could … just take an injection and be a part of it, then, … that’s a lot of reward.
  • — Barry Honig, clinical trial participant and founder of Honig International


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