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I was in deep thought about my collagen cross-linking (CXL) surgery awhile ago. I’ve read every journal article online about epi-off CXL, poured over the interviews with the top surgeons and their speculations on whether CXL will last in the long-term for keratoconus (KC), and thought about everything my top-notch surgeon told me at my pre-op appointment about the efficacy of CXL.
Since epi-off CXL was first performed in Dresden, Germany in 1998, the studies have shown there is no progression of KC and in the small percentage of people who don’t benefit from CXL from the get-go, it is effective when the surgery is repeated. This abstract from 2006, while not long-term, demonstrates the halt in progression. So, why was I worried?
Well, it wasn’t until I found my great optometrist this summer that I learned that although I look like I have KC per my scans and tests, my vision is that of someone with keratoconus, and despite all of the medical literature stating that keratoconus, a primary corneal ectasia, or thinning, can be caused by Ehlers-Danlos syndrome (EDS)—I really have secondary corneal ectasia caused by EDS. Should I change the tagline on my blog? As my optometrist stated, “It’s the same thing more or less.”
Per the “more or less,” here are the differences:
The true cause of KC is not known but there is a connection, at least in part, to faulty collagen in the cornea, but KCers don’t have a systemic disease that causes faulty collagen throughout the body like EDS does. A dry abstract discussing collagen fibrils in KC.
KC tends to show up in one’s teens or early 20s and runs a course of progression before burning out—usually within 20 years. With my secondary corneal ectasia, which apparently has never been researched, there is obviously no burn-out cycle as my body will continue to produce faulty collagen V for the rest of my life due to EDS type II. Therein lies the big problem, or so I think.
With CXL, the weak collagen fibrils in the cornea are tightened up by creating cross-links, much like adding rungs to a ladder. That sounds like a win-win for true KCers and for me. By creating all the cross-links, the cornea is stiffened and aged in essence (see abstract), which burns out the KC as cross-linking and stiffening are naturally occurring processes in normal, aged corneas. That’s good for KCers and in my mind, has no affect on my ectasia with no burn-out cycle and continued production of faulty collagen.
So, why all the worry again? I began to think about cell turnover. Most of the cells in our body turnover in time. What would happen to those nice, cross-linked collagen fibrils when the cells in my cornea, or within the stroma more precisely, turned over? With true KCers, I don’t think it matters as the disease has burned out, but for me, I believe that all the good collagen fibrils will be replaced by the old and it will only be a matter of time before the pseudo-keratoconus—what I’m calling this disease—shows up again.
Then, what are the options? I see none. When KC is severe enough, corneal transplants are the only option, but they reject sooner or later and the healing process is very long. I also have abnormal connective tissue due to EDS, which would make finding a match rather difficult, but that’s an assumption. Lastly, transplanted corneas in KCers who are still progressing can occasionally develop keratoconus again since the disease process is still active. I believe that would be a huge cause for concern in my case due to my faulty collagen production, not to mention my healing and scarring issues from EDS which would make transplants so problematic. A single case report highlighting the recurrence of keratoconus post-transplant.
Now, I was just thinking about all of this and then I noticed my vision got worse all of a sudden, rather like when I first noticed the psuedo-keratoconus. I thought it was from the sclerals I have to wear a few times a week to drive and that it would go away in a couple of days, per usual. That was about a month ago, so it’s not from wearing the sclerals. I don’t have any symptoms aside from more ghosting in my right eye, which was my better eye post-CXL. Now, my left eye with the scar is the better eye and my brain has made that the dominant eye. As the vision in my right eye is worse than the left, it means I’ve lost more than 2 lines of vision in a month or so, which is how this whole debacle started by losing a line every 4-6 weeks on the Snellen chart.
I did have a lot of testing at my 1-year follow-up in late September for the FDA clinical trial, but due to my corneal specialist being the worst ophthalmologist known to humankind, he came into the room for 30 seconds and didn’t say a thing. The reports, which are required by the FDA, never seem to make it to my surgeon in L.A., so who knows if anyone even reviewed them. No one told me anything was awry and I had no reason to suspect anything at the time. I do remember that my VA was the same, not that they’re very accurate at that practice or that it truly represents keratoconic vision.
I spoke with my optometrist about my eye and my concerns and have an appointment next week for an eye exam and corneal topography to see if there is progression. The CXL did work as I got 6 lines of vision back, which is very rare as most get 1 to 2 lines back or none at all. I do know that the cell turnover of the collagen in the stroma is several years and I’m shy of that at about 1 year post-op, but I have no idea what else it could be unless the very mild scar I have in my right eye that’s been stable for 8 months suddenly went wild, in which case I still won’t get my former vision back, and that’s all I want right now, even though most people would be crying in the corner if they had to see the world through my eyes.
I wish I could just get a break and I had to pay so much money for CXL that I didn’t have—I’m sure more than most Americans have in their savings account. When I had the talk with my optometrist about my concerns with CXL, EDS, and the pseudo-keratoconus, he agreed and said, “It’s a whole other monster.” Why didn’t he say that the first time? Maybe they could state that in the medical literature: that a condition that looks, but doesn’t exactly act, like keratoconus can be caused by EDS and it’s a whole other monster, rather than stating that keratoconus can be caused by EDS, period. Perhaps the inept corneal specialist who has M.D. after his name could have told me that after I was diagnosed with Ehlers-Danlos syndrome.
I also found out from my optometrist that if I had had an EDS diagnosis in September of 2012 when I had CXL, instead of in November, that I would have been excluded from the clinical trials. That’s doing wonders to quell my nerves while I sit and twiddle my thumbs and ponder writing a letter to the German ophthalmologist who developed CXL to get his take on its efficacy on my pseudo-keratoconus.
Theo Seiler, M.D., Ph.D., the creator of CXL who also looks exactly like my late grandfather. Hmmm…
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