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Post Info TOPIC: Post graft recurence of the KC: true or false?


Executive

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Posts: 437
Date: Thu Sep 15 11:08 PM, 2005
Post graft recurence of the KC: true or false?
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The answer on this question seems to be very important to understanding of the nature of KC. The article herebelow, published in Cornea in 2003, speaks about the 20 years follow up post graft study of a relatively big number of KC eyes. The conclusion is that in the long run there is the recurence of the KC. I would like to understand is it true or not? Are ther any other studies of this subject? It seems important for understanding since if it is true, it might mean that KC is not a defect of the cornea, but that it is ruther imported or imposed from without, by an agent exterior for the cornea. For exemple, by the absence of aquaporine 5 in the tears of a KC person. If this particualr hypothesis is true, it may signify that, may be it is more relevant to treat lacrimal glands that are supposed to produce AQP 5 and not the corneas themselves? if it is not true - there is no KC recurnece to the grafted corneas- it might mean that the problem is linked to defects in the KC cornea itself, and that KC is strictly internal corneal problem. Anyway, need opinions on the subject. The article and the link are below.

Please click here

Cornea. 2003 May;22(4):317-23. Related Articles, Links

Long-term progression of astigmatism after penetrating keratoplasty for keratoconus: evidence of late recurrence.

de Toledo JA, de la Paz MF, Barraquer RI, Barraquer J.

Centro de Oftalmologia Barraquer, Barcelona, Spain. alvarezt@co-barraquer.es

PURPOSE: To study changes in astigmatism throughout a 20-year period using keratometry and refraction in patients who underwent penetrating keratoplasty (PKP) for keratoconus. METHODS: We reviewed the charts of patients who underwent PKP for keratoconus from 1975 to 1979 and recorded preoperative refraction, stage of keratoconus, laterality of surgery, graft size, suture technique, time of suture removal, keratometry, subjective refraction at 1, 3, 5, 7, 10, 15, 20, and 25 years after suture removal, and slit-lamp findings. RESULTS: Eighty eyes with a mean follow-up of 20 years (range, 15-25) were included in the study. Graft size, suture technique, and time of suture removal had no significant influence on the astigmatism at the last examination. We observed a stabilization of keratometric astigmatism in the first 7 years (4.05 +/- 2.29 D 1 year after suture removal, 3.90 +/- 2.28 D at year 3, 4.03 +/- 2.49 D at year 5, 4.39 +/- 2.48 D at year 7) followed by a progressive increase from 10 years after suture removal until the last follow-up visit (5.48 +/- 3.11 D at year 10, 6.43 +/- 4.11 D at year 15; 7.28 +/- 4.21 D at year 20, and 7.25 +/- 4.27 D at year 25). The mean absolute value of the difference vector (DV) calculated by vector analysis was 7.17 +/- 4.35 D (0-18.33). In 70% of cases, progression of the astigmatism was evident with mean absolute DV of 9.10 +/- 3.65 D. There was a significant correlation between the preoperative and final axis of astigmatism (Pearson r = 0.39, p = 0.0008). There was also a slight positive correlation coefficient between the DV of the eyes in bilateral cases, but it was not significant (Spearman's r = 0.2226, p = 0.34). The major late slit-lamp finding was a peripheral crescent-shaped thinning at the graft-host junction with absence of Bowman's layer on histopathology.CONCLUSION: In spite of refractive stability obtained during the first years after PKP for keratoconus, increasing astigmatism thereafter suggests that there is a progression of the disease in the host cornea.

Publication Types:
Case Reports

PMID: 12792474 [PubMed - indexed for MEDLINE



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yarsky
Anonymous

Date: Sat Sep 17 3:04 AM, 2005
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I think it can happen and does happen as it is documented... also i think other things happen... look at this comprehensive study (as they put it themselfs)

TOP STORIES 6/30/2005
Downward trend seen in endophthalmitis after PK

A comprehensive literature review of the past 40 years indicates that the rate of endophthalmitis after penetrating keratoplasty has declined in the past decade.

Mehran Taban, MD, and colleagues at the University of California, Irvine, and the Wilmer Eye Institute identified and reviewed 66 studies of endophthalmitis after penetrating keratoplasty that were published between 1963 and 2003. Follow-up on the patients ranged from 1 month to 3 years.

A total of 90,549 PK procedures were included in the studies, with an overall 0.382% incidence of endophthalmitis after PK. Most of the studies on endophthalmitis and PK came from the United States (40), followed by Germany, India and the United Kingdom (three studies each), African countries, Australia, Denmark, Israel and Saudi Arabia, with two studies each, and Canada, Finland, France, Singapore, Sweden and Turkey with one study each.

Of note, the authors said, is that over time the rate has declined since the early 1990s. Rates of endophthalmitis after penetrating keratoplasty were 0.142% in the 1970s, 0.376% in the 1980s, 0.453% in the 1990s and 0.2% in the 2000-2003 time frame, the authors said.

“The rate of acute endophthalmitis following penetrating keratoplasty was higher than that following cataract surgery, representing an almost threefold increased risk associated with penetrating keratoplasty,” the authors reported in the May issue of Archives of Ophthalmology. The same group of researchers also recently published an analysis of the incidence of endophthalmitis after cataract surgery.

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Executive

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Date: Sun Sep 18 5:52 PM, 2005
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FOR MORE ON POST GRAFT LONG-TERM EVENTS PLEASE GO TO the BRANCH "JAIL HOUSE", THREAD "LONG TERM MEMORY OF THE CORNEAL TRANSPLANT".

Briefly, in 15-20 years post graft the phenomenon of increasing astigmatism occurs. Doctors can not say if it is the recurence of the KC. It looks as if the residue of the of the host KC cornea continuse to thin as KC cornea does on the periphery. This creates some tension that passes upon donor cornea and coses its deformation labeled as regular astigmatism. The reality however is that people need to fit lenses which seems to be a ruther complex task AGAIN.

Anyway, it is unclear whether KC comes from without or it is an internal affair of the cornea...

-- Edited by Yarsky at 17:53, 2005-09-18

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yarsky
Anonymous

Date: Sun Sep 18 6:37 PM, 2005
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Thanks Yarsky, The topic on "kc more common that previouly thought" covers the topic that a lot of people may have mild/sub-clinical kc.... now doner tissue come from the general public so i think it is probable for these corneas from these cases being implanted to an eye which evolved Keratoconus at one time, then this seed in the doner button can possibliy grow to "full blown" kc due to this... its just one of my theories!

To others who don't know... please read topics like... "Late onset post-keratoplasty astigmatism" and "Cornea Transplantation Fact or Fiction" in the "Jail House" section which covers much about post transplant results...

All The Best

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Senior Member

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Posts: 121
Date: Fri Oct 14 2:33 PM, 2005
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I am an example of post KP recurrance of KC. Both my eyes were transplanted 10 years ago. My left eye had extreme 'oval' keratoconus and my right suffered blinding acute hydrops

After 8 years of 6/9 vision with -6 cyl glasses in the left eye, vision has deteriorated to an extent it cannot be corrected satisfactorily by glasses.

Fortunately I have 6/6 vision in my right eye with -5 cyl glasses.

-- Edited by Eapen at 15:06, 2005-10-14

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Anonymous

Date: Mon Oct 17 1:56 AM, 2005
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Hi Eapen & Yarsky, Here is a good link for newcomers to kc.


http://www.emedicine.com/oph/topic104.htm


 The "e medicine" section for kc has been updated recently. It says that kc does occur after transplant.


On another note, they like most information out-lets still say that transplants are 90% successful, in what capacity exactely? why isn't that detailed so that it is clear for everyone? and successful for who? for you or them? Its our prespective that matters, and for us transplants are not 90% successful...


If transplants are successful by 90%, in that case whats the problem in kc? Why don't they have one? Or why don't we? It's a play with statistics, yes vision may get better than before, but it does not mean you can see more visually by 90% or your transplant lasts for your life time by 90%, or even that you don't need contacts by 90% (actually you need contacts by 60% after a transplant)


No matter what they say, that transplants are needed for only 10% of kcers, this is still too much, its still one in 10 people, more up front its said that transplants happen in 20% of cases of kc, which means one in five people!


Corneal transplants for kc is the the main reason for having corneal transplants! 


All the best



-- Edited by QuintriX at 00:47, 2005-10-18

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Anonymous

Date: Tue Oct 18 2:03 AM, 2005
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Well with this study, including the topics in the "Jail House" section and of course this thread, i think the question asked originally has been answered.

This was a study in our medical library and i forgot all about it... and it has been there for a very long time!

Abstract

Purpose

To report on clinical corneal topography, histopathologic analysis, and fine structure findings in failed grafts after penetrating keratoplasty (PK) for keratoconus (KC).

Design

Retrospective, consecutive, interventional case series with histologic and clinical correlation.

Participants

Twelve corneal buttons were obtained from consecutive patients undergoing repeated PK 10 to 28 years after the initial PK for KC. The indication for regrafting was endothelial deficiency in seven cases, irreversible immune graft rejection in two cases, and corneal ectasia in three cases.

Methods

Removed corneal buttons were examined by light and transmission electron microscopy. A potential correlation between the clinical and videokeratoscopic findings and the microscopic structural observations was analyzed.

Results

Preoperative simulated keratometry measured by TMS-1 (Tomey, New York, NY) or EyeSys CAS (EyeSys Technology, Houston, TX) ranged from 49.8 to 66.1 diopters. A pattern compatible with KC characteristics was observed in all cases. Fine structure analysis revealed Bowman's layer disruption or folds and stromal deposits in all corneal buttons. However, central corneal thinning was not present in any of the removed buttons.

Conclusions

Structure changes compatible with the diagnosis of KC were observed in all donor buttons many years after PK on KC recipients. Recurrence of the KC characteristics may result from graft repopulation by recipients' keratocytes, aging of the grafted tissue, or both.

1 Department of Ophthalmology, CRI, Hôtel-Dieu de Paris, Paris, France
2 Department of Ophthalmology, Hôpital de Poitiers, Paris, France
3 A. de Rothschild Foundation, Paris, France
4 Hadassah, Hebrew University, Jerusalem, Israel
5 INSERM, Paris, France * Correspondence to Francine Behar-Cohen, MD, PhD, INSERM U450, 15-20, rue de l'école de Médecine, 75006, Paris, France.


doi: 10.1016/S0161-6420(03)00617-1

© 2003 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.



-- Edited by QuintriX at 02:07, 2005-10-18

-- Edited by QuintriX at 02:08, 2005-10-18

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