Very curious why you'd take this approach over something like the Boston Keratoprosthesis (https://eyewiki.org/Boston_Type_1_Keratoprosthesis). With a history of cornea rejection, mine has been stable for almost 16 years.
This is the first I'd heard of this, and I did some poking around, and came to the conclusion that this surgery is ~mostly obsolete --- which is an answer (for me) to the question of "don't they have a better substance to use as a lens substrate than tooth?"
Had to bite and check this out after disbelief from the headline that such a thing was going on. Pretty wacky. But also amazing that some doc/researcher out there ran with a hunch to figure out if this was an option to help some people improve their lives. Sci-fi vibes but appreciate the motive.
I wonder how this surgery was originally 1) invented 2) proposed to colleagues.
"Hey peeps, I've been bouncing around this idea lately. So you know how Mrs Smith in room 230 has no eyesight left? Well one of her teeth came off when she fell last night, and I started thinking.."
> Whereas advances in gene therapy, neurotrophic factor administration, and electric field stimulation have shown promise in preclinical optic nerve crush injury models, researchers have yet to demonstrate efficacy in optic nerve transection models—a model that more closely mimics WET. Moreover, directing long-distance axon growth past the optic chiasm is still challenging and has only been shown by a handful of approaches. [5–8]
> Another consideration is that even if RGC axons could jump across the severed nerve ending, it would be impossible to guarantee maintenance of the retinal-cortical map. For example, if the left eye were shifted clockwise during nerve coaptation, RGCs in the superior-nasal quadrant of donor retinas would end up synapsing with superior-temporal neurons in the host's geniculate nucleus. This limitation also plagues RGC-specific transplantation approaches; its effect on vision restoration is unknown.
> Abstract: [...] Serial electroretinography confirmed retinal responses to light in the transplanted eye. Using structural and functional magnetic resonance imaging, the integrity of the transplanted visual pathways and potential occipital cortical response to light stimulation of the transplanted eye was demonstrated. At 1 year post transplant (postoperative day 366), there was no perception of light in the transplanted eye.
> With nervous coaptation, 82.9% of retinas had positive electroretinogram signals after surgery, indicating functional retinal cells after transplantation. Results on optic nerve function were inconclusive. Ocular-motor functionality was rarely addressed.
How to target NGF(s) to the optic nerve?
Magnets? RF convergence?
How to resect allotransplant and allograft optic nerve tissue?
How to stimulate neuronal growth in general?
Near-infrared stimulates neuronal growth and also there's red light therapy.
Nanotransfection stimulates tissue growth by in-vivo stroma reprogramming.
How to understand the optic nerve portion of the connectome?
The Visual and Auditory cortices are observed to be hierarchical.
Near-field imaging of [optic] nerves better than standard VEP Visual Evoked Potential tests would enable optimization of [optic nerve] transection.
> So, to run the same [fMRI, NIRS,] stimulus response activation observation/burn-in again weeks or months later with the same subjects is likely necessary given Representational drift.
> [...] have successfully demonstrated that a beam of light can not only be confined to a spot that is 50 times smaller than its own wavelength but also “in a first of its kind” the spot can be moved by minuscule amounts at the point where the light is confined.
Optical tweezers operating below the Abbe diffraction limit are probably of use in resecting neurovascular tissue in the optic nerve (the retina and visual cortex)?
> “What’s interesting is that these Müller cells are known to reactivate and regenerate retina in fish,” she said. “But in mammals, including humans, they don’t normally do so, not after injury or disease. And we don’t yet fully understand why.”
/? Regenerative medicine for ophthalmologic applications
At first I was curious if they'd included any pictures of what it actually looks like, but when I saw the pictures I definitely came to doubt my decision. So for the feint of heart, beware.
If you damage somebody's eye which happens to have their tooth embedded in it, then justice means takeing one of your eyes and one of your teeth. Pretty sure it's a footnote in Hammurabi somewhere...
The title "For the 1st time in Canada, surgeons put teeth in patients' eyes to restore sight" is much clearer than "Surgery aims to restore sight by implanting a telescopic lens in a tooth".
First, the tooth is put into the eye — used as biocompatible material to hold the lens. Second, the surgery is 60 years old and has something like a 94% success rate after 27 years, so it's hardly fair to say "surgery _aims_ to restore sight". It almost certainly will restore sight. The part that is interesting in this story is that it's an uncommon surgery that is happening only for the first time _in Canada_.
The linkbaity effect of the original wasn't obvious until we started seeing it in the comments. Once that happens, though, we've learned that replacing the title with more neutral wording is the #1 thing to do to get a thread back on topic and into curiosity land (as opposed to sensational land).
Very curious why you'd take this approach over something like the Boston Keratoprosthesis (https://eyewiki.org/Boston_Type_1_Keratoprosthesis). With a history of cornea rejection, mine has been stable for almost 16 years.
This is the first I'd heard of this, and I did some poking around, and came to the conclusion that this surgery is ~mostly obsolete --- which is an answer (for me) to the question of "don't they have a better substance to use as a lens substrate than tooth?"
Why is it obsolete?
They still do it, obviously, but we have better artificial corneas now.
I'd like an answer that is more than just a sound bite.
It's nothing like as as grotesque as the headline makes it sound. Worth reading.
Suggested headline: "Surgery implants tooth material in eye as scaffolding for lens" or something like that?
Ok, let's try that. Thanks!
Had to bite and check this out after disbelief from the headline that such a thing was going on. Pretty wacky. But also amazing that some doc/researcher out there ran with a hunch to figure out if this was an option to help some people improve their lives. Sci-fi vibes but appreciate the motive.
Oh great, now I have to brush my eyes before I go to bed too.
I wonder how this surgery was originally 1) invented 2) proposed to colleagues.
"Hey peeps, I've been bouncing around this idea lately. So you know how Mrs Smith in room 230 has no eyesight left? Well one of her teeth came off when she fell last night, and I started thinking.."
Same here. How TF people just come up with such ideas.
/? eye transplant https://hn.algolia.com/?q=eye+transplant
https://scholar.google.com/scholar?q=related:ZlcYhwhYqiUJ:sc...
From "Clinical and Scientific Considerations for Whole Eye Transplantation: An Ophthalmologist's Perspective" (2025) https://tvst.arvojournals.org/article.aspx?articleid=2802568 :
> Whereas advances in gene therapy, neurotrophic factor administration, and electric field stimulation have shown promise in preclinical optic nerve crush injury models, researchers have yet to demonstrate efficacy in optic nerve transection models—a model that more closely mimics WET. Moreover, directing long-distance axon growth past the optic chiasm is still challenging and has only been shown by a handful of approaches. [5–8]
> Another consideration is that even if RGC axons could jump across the severed nerve ending, it would be impossible to guarantee maintenance of the retinal-cortical map. For example, if the left eye were shifted clockwise during nerve coaptation, RGCs in the superior-nasal quadrant of donor retinas would end up synapsing with superior-temporal neurons in the host's geniculate nucleus. This limitation also plagues RGC-specific transplantation approaches; its effect on vision restoration is unknown.
"Combined Whole Eye and Face Transplant: Microsurgical Strategy and 1-Year Clinical Course" (2024) https://pubmed.ncbi.nlm.nih.gov/39250113/ :
> Abstract: [...] Serial electroretinography confirmed retinal responses to light in the transplanted eye. Using structural and functional magnetic resonance imaging, the integrity of the transplanted visual pathways and potential occipital cortical response to light stimulation of the transplanted eye was demonstrated. At 1 year post transplant (postoperative day 366), there was no perception of light in the transplanted eye.
"Technical Feasibility of Whole-eye Vascular Composite Allotransplantation: A Systematic Review" (2023) https://journals.lww.com/prsgo/fulltext/2023/04000/Technical... :
> With nervous coaptation, 82.9% of retinas had positive electroretinogram signals after surgery, indicating functional retinal cells after transplantation. Results on optic nerve function were inconclusive. Ocular-motor functionality was rarely addressed.
How to target NGF(s) to the optic nerve?
Magnets? RF convergence?
How to resect allotransplant and allograft optic nerve tissue?
How to stimulate neuronal growth in general?
Near-infrared stimulates neuronal growth and also there's red light therapy.
Nanotransfection stimulates tissue growth by in-vivo stroma reprogramming.
How to understand the optic nerve portion of the connectome?
The Visual and Auditory cortices are observed to be hierarchical.
Near-field imaging of [optic] nerves better than standard VEP Visual Evoked Potential tests would enable optimization of [optic nerve] transection.
VEP: https://en.wikipedia.org/wiki/Evoked_potential#Visual_evoked...
Ophthalmologic science is important because - while it's possible to fight oxidation and aging - our eyes go.
Upper-atmospheric radiation is terrible on eyes. This could be a job for space medicine, and pilots.
Accomodating IOLs that resist UV damage better than natural tissue: Ocumetics
From "Portable low-field MRI scanners could revolutionize medical imaging" (2023) https://news.ycombinator.com/item?id=34990738 :
> Is MRI-level neuroimaging possible with just NIRS Near-Infrared Spectroscopy?
From "Language models can explain neurons in language models" https://news.ycombinator.com/item?id=35886145 :
> So, to run the same [fMRI, NIRS,] stimulus response activation observation/burn-in again weeks or months later with the same subjects is likely necessary given Representational drift.
"Reversible optical data storage below the diffraction limit (2023)" [at cryogenic temperatures] https://news.ycombinator.com/item?id=38528844 :
> [...] have successfully demonstrated that a beam of light can not only be confined to a spot that is 50 times smaller than its own wavelength but also “in a first of its kind” the spot can be moved by minuscule amounts at the point where the light is confined.
Optical tweezers operating below the Abbe diffraction limit are probably of use in resecting neurovascular tissue in the optic nerve (the retina and visual cortex)?
"Real-space nanophotonic field manipulation using non-perturbative light–matter coupling" (2023) https://opg.optica.org/optica/fulltext.cfm?uri=optica-10-1-1... :
> "One can write, erase, and rewrite an infinite number of times,"*
"Retinoid restores eye-specific brain responses in mice with retinal degeneration" (2022) https://news.ycombinator.com/item?id=33129531
Fluoxetine increases plasticity in the adult visual cortex; https://news.ycombinator.com/item?id=43079501
Zebrafish can regrow eyes,
From the "What if Eye...?" virtual eyes in a petri dish simulation: https://news.ycombinator.com/item?id=43044958 :
> [ mTor in Axolotls, ]
"Reactivating Dormant Cells in the Retina Brings New Hope for Vision Regeneration" (2023) https://neurosciencenews.com/vision-restoration-genetic-2318... :
> “What’s interesting is that these Müller cells are known to reactivate and regenerate retina in fish,” she said. “But in mammals, including humans, they don’t normally do so, not after injury or disease. And we don’t yet fully understand why.”
/? Regenerative medicine for ophthalmologic applications
At first I was curious if they'd included any pictures of what it actually looks like, but when I saw the pictures I definitely came to doubt my decision. So for the feint of heart, beware.
Like something out of a Lynch or Cronenberg film. Definitely not what I was expecting
Surprised they didn't do a tattoo of an eye or something...
Yeah, that is something. Reminds me a bit of the eye worn by Charles Dance's character in Last Action Hero.
What are the moral and legal implications of such a surgery? An eye for a tooth, a tooth for an eye?
If you damage somebody's eye which happens to have their tooth embedded in it, then justice means takeing one of your eyes and one of your teeth. Pretty sure it's a footnote in Hammurabi somewhere...
[stub for offtopicness]
You don't need horror movies with such science.
Or at any rate with such headlines.
We've adopted the more neutral subtitle now.
The title "For the 1st time in Canada, surgeons put teeth in patients' eyes to restore sight" is much clearer than "Surgery aims to restore sight by implanting a telescopic lens in a tooth".
First, the tooth is put into the eye — used as biocompatible material to hold the lens. Second, the surgery is 60 years old and has something like a 94% success rate after 27 years, so it's hardly fair to say "surgery _aims_ to restore sight". It almost certainly will restore sight. The part that is interesting in this story is that it's an uncommon surgery that is happening only for the first time _in Canada_.
Those are good points. dcminter suggested a different wording, which might have a less agitating effect, so we can try that for a while.
https://news.ycombinator.com/item?id=43208774
Thanks! Your hard work is appreciated.
An.. eye-tooth, if you will.
The title should be edited. It's missing the main part which is that the tooth will be implanted in the eye of the patient, not left in their mouth.
Good point! More at https://news.ycombinator.com/item?id=43209012.
Apparently the title was edited since I posted it—it was originally about the same as the article.
You did nothing wrong! it's a fine submission, and the site guidelines (https://news.ycombinator.com/newsguidelines.html) call for using the original title "unless it misleading or linkbait".
The linkbaity effect of the original wasn't obvious until we started seeing it in the comments. Once that happens, though, we've learned that replacing the title with more neutral wording is the #1 thing to do to get a thread back on topic and into curiosity land (as opposed to sensational land).
Makes sense—thanks for sharing this!
An eye for an (eye|tooth) and a tooth for a (tooth|eye).
I guess it does bring new meaning to the phrase “eye teeth”.
I'm looking through Gary Gilmore's teeth
Oh, it's your own teeth they use. That answers one question.
Okay, what the actual fuck?