[gdebel]

Corneal surgeon here ! (Note : I never implanted a keratoprosthesis. This is an extremely unfrequent procedure, usually performed by a handful of surgeons in a given country). Some insights about this topic. This looks like a great device (never heard before !). This is a keratoprosthesis, meaning this is a last recourse, "no-hope-except-maybe-that", procedure. However it looks infinitely more simple and respectful of the eye integrity than current keratoprosthesis, and, if it really acts like a scaffold for native corneal cells and allows a colonization and the obtention of a satisfying corneal surface, it could be a game changer. It is way too soon to know.

A significant percentage (I would say around 40-70%, depending on the country) of corneal graft indications originates from pathologies coming from the inner layer of the cornea (corneal endothelium). Posterior lamellar graft (DMEK) allows today to change only the thin cellular layer which is pathological, with an usually quick recovery. Even the best performing keratoprosthesis won't replace this procedure, because we care to preserve the eye's integrity as much as we can.

It is interesting to remember that corneal transplantation is a very special topic because the cornea is not vascularized, meaning less rejection. There still is, of course, but the outcomes as usually good. Keratoprosthesis are today indicated when previous grafts where rejected, when the other structures of the eye are healthy, and when the vision is extremely low. This allows to gain a few years of very low vision before, usually, losing the eye due to infection or high ocular pressure.

The technology presented has the potential: - to replace current keratoprosthesis and lower the threshold to decide to perform the procedure : yes, almost sure if the device is well-tolerated - to replace perforating keratoplasty (full corneal replacement, unfrequent today) where the cornea is damaged in its entirety: maybe, highly uncertain for the moment. That would be an incredible step forward, a revolution in our practice. - to replace anterior lamellar keratoplasty, where the anterior wall of the cornea is replaced : highly unlikely - to replace posterior lamellar keratoplasty, where the cornea lacks transparency because of inner layer cellular dysfunction: almost impossible.

I would also like to raise awareness on the topic of eye rubbing. The eye surgeon community progressively discovers the highly harmful consequences of vigorous and daily eye rubbing. A few teams (mine, notably) even think that it is the single trigger for keratoconus. You will find a nice illustrations of what a rubbed eye looks like in MRI I by googling "don't rub your eye" (this is me in the MRI ;-) and more explanations here : https://defeatkeratoconus.com/

[mkl]

I would like to second the eye rubbing awareness. I have keratoconus in both eyes, and had two (donor) corneal transplants in the 1990s, in my teens. Even with them, my sight is not great, as the distortions from the transplant scarring and residual keratoconus around the edges are only partially correctable with regular glasses lenses (I think these artificial corneas would not be better). I had bad hayfever as a kid (and still do sometimes now) and rubbed my eyes a lot. I now think it's the most likely cause.

Don't let your kids rub their eyes!

[EvanAnderson]

I am in a similar boat-- fairly bad animal allergies and hay fever as a child accompanied with frequent and vigorous eye rubbing and now keratoconus (though, fortunately, not so far-progressed as to need corneal transplants).

My daughter has the same characteristic long eyelashes that I do, and exhibits allergies (though much less severe than mine). My wife and I have made a very strong effort to prevent her from eye-rubbing. She's old enough now to understand why we were so adamant about it.

I'm seeing elsewhere in this thread that nocturnal eye rubbing can be a problem. I never thought about that and it's a bit disturbing. I do remember waking-up with my eyes plastered shut with hardened mucus as a child.

[Aerroon]

Interesting! How much eye rubbing are we talking about? Several times a day? Once a day? Once a week? Any tips on stopping the habit?

[gdebel]

To start with, full disclosure : this is a controversial topic. The majority of eye surgeons are still convinced that there is a genetic predisposition to keratoconus, and that eye rubbing is an optional trigger. Other (a growing number) think that this is the sole responsible of keratoconus.

My mentor is the main proponent of the eye rubbing theory. I was a skeptic, and became convinced by learning with him how to properly interview patients on this subject, how to prevent eye rubbing, and by seeing the absence of progression after full awareness of the patients (without cross-linking. We don't do any CXL in my department, ever. KC screening and care is one of our main activity: not doing CXL is a financial loss). My mentor's website : https://www.gatinel.com/recherche-formation/keratocone-2/no-... (No conflict of interest except loyalty).

The main difficulty is that it is almost impossible to design an experiment to prove the theory (if someone has a genius idea, please don't hesitate). Usually other surgeons or students become convinced after visiting the department and spread the good practices back home : still a long way to go.

The harmful eye rubbing is made with the hard parts of the hand (knuckles). It is frequently nocturnal and almost everytime ignored. Awareness comes when the patient has been informed and told to look for this habit. At the second consultation, the eye rubbing is reported in the vast majority of cases. I count the keratoconus patients that deny eye rubbing after 2-3 consultations on one hand. We prescribe a transparent eye shell to sleep with when the patient denies eye rubbing : it allows them to realize that they rub during the night. We prescribe eye drops to ease the eye irritation which triggers rubbing, and instruct to rub the inner part of the eyelid, against the nose (no eye deformation) if necessary. Sleep position is frequently pathological too (eye vs hand or arm contact. In those cases the KC is very asymetrical).

Doctors in our team can predict the eye rubbing habit frequency and intensity by looking at a corneal topography. It is incredible that the role of this habit was ignored so long. I suppose that we doctors don't talk enough with our patients. The financial incentive of performing CXL and surgeries is so clearly detrimental the the adoption of those practices.

[keratothrowaway]

Hi, I am really interested in reading this conversation, as I have keratoconus and had CXL surgery about ten years ago, and am very happy with it. The CXL stopped the keratoconus progressing and I only need to wear glasses instead of the more invasive things other patients mention (contact lenses, corneal grafts and transplants, etc).

It would be good if this intervention to convince patients to cease eye rubbing was more common in keratoconus patients. There is often a delay of several months between when keratoconus is suspected or diagnosed and CXL is carried out (in my case I had to wait 6 months in one eye and 9 months in the other, during which time it got a bit worse).

About eye rubbing, yes there should be more awareness of it! In practical terms, I would recommend that everyone tries wearing an eye-mask when they’re asleep (I recently bought this one, and I'm happy with it https://www.amazon.co.uk/gp/product/B07DW32QYJ ). This is because it's more difficult to notice and prevent yourself from rubbing your eyes when you're half-asleep.

There are several reasons why I like wearing an eye mask while in bed, and some even apply to people who don’t have keratoconus: 1. It stops me rubbing my eyes when I'm in bed. 1. It might stop allergens getting into my eyes when I'm asleep, for example I notice much less rheum on my eyes when I wake up in the morning. When I’m in bed is when I notice that my allergies are worst. 3. It helps me sleep better, it's like having blackout curtains in my room. 4. If I want to get up in the middle of the night, I will be able to see better in the dark.

[Aerroon]

Are there any correlations between people who wear contacts and have keratoconus? I'm asking, because handling contacts effectively requires you to rub the eyes a little every time you take the contacts out. Or is that kind of deformation not enough?

[gdebel]

(empirical, non scientific opinion): usually, wearing contact lenses tends to prevent vigorous eye rubbing, during the day. Also, people with sensitive, itchy eyes tend to avoid contact lenses: this is a two-way relationship. Nefarious eye rubbing is usually related to a daily, compulsory "habit", involving a vigorous pressure on the eye using the knuckles or the side of the index, also frequently present while sleeping.

[loceng]

I'm curious if you're familiar with the stromal stem cell research for regenerating deeper corneal tissues?

Research from University of Pittsburgh, successful on mice/rat models, was taken to India for human clinical trials with pretty great success healing severe chemical burns and scarring to the cornea. Here's video of them talking about their effort to get it FDA approved (will take 5 years), I linked it to where it shows the before and after results: https://youtu.be/q_obgXSeLaU?t=1586

[capnahab]

(Not remotely competing) neurosurgeon here. Vision never ceases to amaze me in its robustness. Patients with long-standing (years) visual field defect from pituitary tumour will recover their vision within minutes of it being decompressed. One of the most satisfying things I do is ask the patient in the recovery area if they can see the time on the clock opposite them, - the operation having finished 30 mins ago. Most can, - this says much more about nature, nerve compression and neuronal plasticity than the surgery.

[kak9]

This is really fantastic reply and context. Thanks for posting this!

When you see research like this, assuming all things trend positive (big if of course) what is the timeframe one expects to see it make its way to mainstream application?

[gdebel]

If the outcomes are as great as they look, I think one could expect "mainstream adoption" (specialized centers and unfrequent indications) in 2-3 years ? This is a hard guess!