Crosslinking - possible permanent flap solution?

[dckiwi]

Hello

I underwent Lasik surgery approximately 18 months ago. I have experienced excellent results with absolutely no issues – I attribute this to the skill of the surgeon and the compatibility of my eyes for this type of surgery. Recently, however, it occurred to me that flap dislocation could become an issue (albeit rare). Hence, I have scaled back anything that could present a problem, such as contact sports, etc. Late traumatic dislocation was not discussed when I had my procedure.

I have a question and haven't found adequate or consistent information online and perhaps it's a subject you are familiar with. In your research/exposure to the topic, do you think riboflavin/UVA cross linking can in fact completely seal this flap mechanically by increasing the strength of the cornea in otherwise successful surgeries? Or is this treatment something that is only reserved for side effects. Even then, when it is used to treat a side effect, is the eye stronger?

I’ve become somewhat depressed after quitting sports, etc. I understand that the likelihood of dislocation is extremely low, but not zero, which I why I have decided to “lay-low”.

What sparked my interest was this article: http://www.medicalnewstoday.com/articles/148611.php, in particular this quote:

...the National Institutes of Health grant renewal will enable the lab group to test a possible solution that would strengthen the stromal flap and allow it to permanently bind back to the cornea after LASIK, Conrad said. It uses a combination of riboflavin and UVA light to permanently cross-link the connective tissue of the flap to the underlying corneal connective tissue.

Thanks in advance, I respect you opinion(s).

[LasikExpert]

The idea of using Corneal Collagen Crosslinking with Riboflavin (CxL) to affix the Lasik flap to the underlying stroma is one of theoretical speculation at this point, and I like to say that nothing screws up a perfectly good theory faster than reality.

The theory behind CxL is that the natural bonds that hold cells close to one another can be strengthened by the application of UV light of a wavelength of 370 nm for 30 minutes. The mechanics behind CxL are really not fully proven. There is a stiffing of the cornea with CxL, but I have not seen anything that affirms the stiffening is because CxL caused the bonds between cells to strengthen and thereby make the cornea more stiff; because the primary cells are aged quickly due to the UV light and the cells themselves become stiff - not the bonds between them; or some other healing response not yet clarified.

For CxL to work across a Lasik flap interface one must assume that there is some crosslinking in the first place. So far, CxL has only been shown to provide improvement in existing crosslinked cells, not creating crosslinking in cells that have been severed. That would be a big jump, excuse the pun.

Additionally, the Lasik flap interface is no longer the same as the untouched area of the cornea. It is a healed wound. Even with normal healing, the center of the Lasik flap contributes very little to the structural integrity of the cornea, less than about 3% of normal. This indicates strongly that the corneal cells in the center of the corena are not affixing to each other in the manner by which they were aligned and affixed before the flap.

BTW: The periphery of the corneal flap heals quite solidly. Think of the Lasik flap as a Tupperware lid held firmly at the edges but not firmly in the center. You may want to learn more about Lasik flap healing.

At this point in development CxL seems to be an answer for which the correct question has not been found. It is great that the wise are coming up with all these different potential applications, but healthcare has a long history of expecting too much of the new.

Don’t be surprised the theory behind the concept is not proven, yet CxL is being performed in many countries successfully and is going through an FDA clinical trail in the US. We don’t know what electricity is, but that does not mean we need to be in the dark.

One doctor in the US is performing a crosslinking technique that is not part of the FDA clinical trial. He calls it C3R.

[dckiwi]

Hi Glenn,

Thanks for the very informative post - it confirms much of what I have read online.

I don't think there is any "silver bullet" for permanent flap healing, but I don't think the flap issue is as bad as some websites seem to lament. Personally, I think some of the more common adverse effects (night vision, halos, etc) would pose a greater problem as they would seem more persistent and harder to fix.

I'm just going to continue life, but take a pragmatic approach and scale back some of the more riskier activities, such as swapping martial arts for yoga....

Thanks again for your comments.

Rgds.

[LasikExpert]

I don't think the flap issue is as bad as some websites seem to lament.

LOL I know those people all too well...I'm a plaintiff against them. They would have you believe that if you sneeze the Lasik flap will blow off and never be seen again - or you will never see again - or both. There are a handful of people who have created multiple websites, use multiple aliases, and seem to have nothing else in their lives to do but post the same rhetoric again and again using alias after alias and website after website. One of them has admitted in court documents to four aliases, and I've traced her to about a half-dozen more. Their technique works. They make it appear there is a chorus of agreement with their anti-Lasik views, when it is actually a noisy trio hiding behind the Internet's anonomitiy. What is worse is that there are sincere Lasik complications help groups that get a bad rap from the loonies.

The Lasik flap does heal, but not like a cut on your arm. The interface is always different.

If you want to see the real Lasik results, look at what actual patients (not aliases) say in the USAEyes Competence Opinion Relative to Expectations (CORE) patient survey.

I'm just going to continue life, but take a pragmatic approach and scale back some of the more riskier activities, such as swapping martial arts for yoga....

That actually sounds like an advantage of Lasik!

Many people in contact sports, such as professional football players, pro basket ball players, skiiers, divers, etc., have had Lasik and don't have their flaps blowing in the wind. Lasik flaps can dislodge, but it takes a significant amount of force. Use a bit of common sense and eye protection is the best prescription.

[dckiwi]

Thanks again Glenn.

Yes, I quickly realized there were a few sites with the all same info. It didn't take me long to twig it's just a few individuals behind it. What they are doing though is just plain wrong in my opinion, I'm sure you agree! People (myself included) read these sites not knowing that it's just all hype, but we're left with all these self doubts. Even when we realize the truth behind the sites, it's too late - as they old saying goes: "you can't un-ring a bell". Even though I know the technology is very safe, had I not read some of those sites, I would not have panicked and wrapped my eyes in cotton wool so to speak.

I believe in freedom of speech, etc but it's very frustrating when mis-information is touted as gospel.

I read an interesting article recently whereby compressed air was fired at rabbits, emulating a finger poke. 9 days after surgery, 23% of flaps could not be budged, even with the maximum amount of pressure. Just 9 days afterward. That's saying something. I bet you don't see that on the hype sites.

Keep up the good work on this site - it's very unbiased, yet realistic (i.e. you freely admit there are issues with refractive surgery, but put these issues into context).

I *will* be going back to martial arts!

Thank you!

[LasikExpert]

I read an interesting article recently whereby compressed air was fired at rabbits, emulating a finger poke. 9 days after surgery, 23% of flaps could not be budged, even with the maximum amount of pressure. Just 9 days afterward. That's saying something. I bet you don't see that on the hype sites.

US Navy aviators were restricted for years to PRK or similar surface ablation techniques because of fears of the Lasik flap during ejection. To test the theory, they blew bunnies out of simulated ejector seats at multi-mach speeds. They had good enough results that Navy pilots - including Top Gun pilots - may now have Lasik.

Poor bunnies, but medically safe Lasik.

Not only do the "the Lasik flap never heals" people ignore these kinds of facts, but they also attacked the study's lead surgeon on their websites. You are correct that you cannot un-ring a bell, and that is exactly what some people with their own agendas seem to hope for.

[tszchun8]

My little experience- I play soccer very often, I can say that shoot in face is okay, it won't dislodge my flap.
Last two months, My head crashed with other players when I was heading the ball, my right eyelip broke, it cost me 6 stitches. My right eye swelled a lot but the flap was still okay
last month, unfortunately, the same thing happened, this time, my nasal bone fractured and facial bone incomplete fractured. There was still no problem in my lasik flap.

Of course, the healing ability and the strength of lasik flap is differented for everyone. But in my experience, the flap was still able to sustain a certain amount of force. There is still a risk, but it's a very small risk.

lasik date14/6/2008, I rested 3 months before came back to the football field
before lasik, both eyes -9.50
after lasik 20/20 for both eyes
intralase lasik US$1000 :evil: ( extremely cheap in China, I didn't lived in China, but I traveled to China to take the surgery.)
p.s. sorry for my bad english

[LasikExpert]

You English is excellent and the information you provide is invaluable. Thanks!

[dckiwi]

Hi,

Yes, thanks for that, it adds a bit of perspective. It has occurred to me that I have taken a few knocks to the eye region, but it was before I read all the shock-sites, so it never even bothered me.

Come to think of it, I was eye-gouged playing back-yard rugby a few months back, I had a bruise on my cheek and my eye was a little tender, but I didn't give it s second thought..... No worries!

[LasikExpert]

You are an example of how strong the Lasik flap heals and how not to treat your eyes!

[-RanZ-]

what would happen if something happened and the flap actually partially or fully was ripped from the eye? Are you basically screwed or can something be done to regain some vision? I'm not actually worried about that happening but curious about worse case scenario.

[LasikExpert]

If the flap is recovered and is complete, it can be repositioned and will secure. If the flap is lost or beyond repair, then specialized contact lenses may work, but most likely additional laser surgery to reshape the cornea to make it more regular would be required.