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.
There are some circumstances where a keratoprosthesis won’t work, particularly if the eye has no tear production. OOKP is a good technique in some where they are blind in both eyes from severe ocular surface issues but the retina is still intact. It is very resource intensive and involves a number of subspecialty areas, and so is a last ditch effort for the bilaterally blind.
> Many studies have shown the incidence of repair procedures and worse final vision outcomes were higher in groups with autoimmune conditions (SJS, OCP). The difference in outcomes appears to be related to the degree and cumulative past period of inflammation. Overall most favorable outcomes are achieved in non-cicatrizing conditions, followed by ocular burns and OCP with the worst outcomes in SJS patients.
The patient in the article was a SJS patient
> The massage therapist says he could see just fine until he was 13 years old, when he took some ibuprofen after a school basketball game, triggering a rare auto-immune reaction known as Stevens-Johnson syndrome.
>It involves removing a patient's tooth, usually the canine, installing a plastic optical lens inside it, and then implanting the whole thing into the eye.
How fitting that the material usually comes from eyeteeth!
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.
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?"
Not that i’m doubting you. Just that i also did some poking around and found this statement published in 2013: “The Falcinelli OOKP (MOOKP), where adequately performed, is now recognised internationally as giving the best, long-term visual and retention results among all keratoprostheses, especially in a dry eye.” [1]
Curious if the difference between what you found and what i found is time (perhaps what was in 2013 the best threatment has been superseeded by better ones since), or differences in opinions among practicioners. Especially because the “where adequately performed” sentence part makes my spider sense tingle about the one i found.
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.."
One thing I don't understand is how the surgeon ensures the lens is positioned correctly. We're talking about a rigid lens that can no longer be controlled via muscles, right? Doesn't any misalignment mean you get a fuzzy image at best? And even if you can get a sharp image for some given, fixed distance, you still can't control whether to focus on near things or far things when you look, right??
If you've ever played around with a magnifying glass, they accept a surprising amount of tilt. It's not a clear image, but a blurry image is better than no image.
This surgery is for people who've had their eyes destroyed by chemicals or similar. They don't always have the structure remaining for any finer control.
I mean it's a bit gross, but the version of the headline I saw made me think it was some kind of in-mouth camera and I was wondering how on earth they routed the optic nerve down there (silly of me perhaps, because I've read about this before, but that's how it took me initially).
Grossness aside, it's pretty interesting that the need for biocompatibility made this something worth considering at all though.
So these sciency folks have managed to move tooth from the mouth to the eyes but still want to pluck some teeth off to move around some other teeth parked wrongly; and then expect me to have something installed forever to keep them in place, even after all that planned uprooting. Huh.
fwiw in the US, typically even extremely messed up teeth don't require removal to fix with orthodontics. Some ortho places will advocate it because it's easier. But if you get a few quotes in a big city usually someone can do it without pulling.
Wisdom teeth often do require pulling cus they literally don't fit (idk if this is an evolution thing - were people losing teeth normally enough that a new one coming in wasn't overcrowding?)
I think this is an evolution thing but not in that way. I believe when our diets changed due to agriculture the foods we ate got softer and our mouths subsequently changed [1]
What are those procedures that I can discuss with an orthodontist? Because almost everybody here (not in US) tries to sell one package or the other and even with that they add teeth removal and life long retainer and what not.
As someone with Type 2 diabetes, I am eternally grateful for everyone who works on future eye surgery advancements. Especially for people who work in tech, it's nearly a death sentence.
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).
> 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
