Journal Mobile Options
Table of Contents
Vol. 218, No. 2, 2004
Issue release date: March–April 2004
Ophthalmologica 2004;218:136–140
(DOI:10.1159/000076150)

Thermomechanical Behavior of Collagen-Cross-Linked Porcine Cornea

Spoerl E. · Wollensak G. · Dittert D.-D. · Seiler T.
Departments of aOphthalmology and bPathology, Universitätsklinikum CGC, Dresden, Germany; cInstitut für Refraktive und okuloplastische Chirurgie (IROC), Zürich, Switzerland

Individual Users: Register with Karger Login Information

Please create your User ID & Password





Contact Information











I have read the Karger Terms and Conditions and agree.

To view the fulltext, please log in

To view the pdf, please log in

Abstract

Purpose: Collagen cross-linking using combined riboflavin/UVA treatment has been shown to increase the biomechanical rigidity of the cornea and has been used successfully for the treatment of progressive keratoconus. From morphological and biochemical investigations, a different degree of cross-linking for the anterior and posterior stroma by the treatment is suggested. The present study was undertaken to better evaluate this effect by testing the thermomechanical behavior. Methods: Ten 10 × 5 mm corneal strips from porcine cadaver eyes enucleated within 5 h post mortem were cross-linked using the photosensitizer riboflavin and UVA irradiation (370 nm, irradiance = 3 mW/cm2) for 30 min and compared to ten untreated corneal strips and ten corneal strips cross-linked with 0.1% glutaraldehyde. The temperature in a water bath was raised from 60 to 95°C with temperature increments of 1°C per minute. The hydrothermal shrinkage of the corneal strips was measured in 2.5°C steps using a micrometer. In addition, six 10-mm whole corneal buttons were cross-linked with riboflavin/UVA and immersed into water at 70 or 75°C. Results: The maximal hydrothermal shrinkage for the untreated control specimens and the posterior portion of the riboflavin/UVA-treated corneas was at 70°C, for the anterior portion of the cornea cross-linked by riboflavin/UVA at 75°C and for glutaraldehyde-cross-linked cornea at 90°C. In the cross-linked corneal buttons, a typical mushroom-like shape was observed at 70°C and a cylinder shape at 75°C. Conclusions: The different degree of collagen cross-linking in the corneal stroma after riboflavin/UVA treatment is reflected by the differences in the maximal shrinkage temperature of the anterior and posterior portion. Therefore, in the corneas cross-linked with riboflavin/UVA a higher shrinkage temperature was observed for the anterior portion of the cornea (75°C) compared to the posterior stroma (70°C) due to the higher degree of cross-linking of the anterior stroma. The anterior localization of the cross-linking effect is advantageous for the endothelium and for the preservation of the anterior corneal curvature.



Copyright / Drug Dosage

Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.

References

  1. Wollensak G, Spoerl E, Seiler T: Riboflavin/ultraviolet-A-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003;135:620–627.
  2. Wollensak G, Spoerl E, Seiler T: Stress-strain measurements of human and porcine corneas after riboflavin-ultraviolet-A-induced cross-linking. J Cataract Refract Surg 2003;29:1780–1785.
  3. Spoerl E, Wollensak G, Seiler T: Resistance of crosslinked cornea against enzymatic digestion. Curr Eye Res 2004; in press.
  4. Wollensak G, Spoerl E, Wilsch M, Seiler T: Keratocyte apoptosis after corneal collagen-crosslinking using riboflavin-UVA treatment. Cornea 2004;23:43–49.
  5. Wollensak G, Wilsch M, Spoerl E, Seiler T: Collagen fiber diameter in the rabbit cornea after collagen-crosslinking by riboflavin/UVA. Cornea 2004; in press.
  6. Müller LJ, Pels E, Vrensen GFJM: The specific architecture of the anterior stroma accounts for maintenance of corneal curvature. Br J Ophthalmol 2001;85:437–443.
  7. Simionescu D, Simionescu A, Deac R: Mapping of glutaraldehyde-treated bovine pericardium and tissue selection for bioprothetic heart valves. J Biomed Mater Res 1993;27:697–704.
  8. Charulatha V, Rajaram A: Influence of different crosslinking treatments on the physical properties of collagen membranes. Biomaterials 2003;24:759–767.
  9. Allain JC, Lous M, Cohen-Solal L, Bazin S, Maroteaux P: Isometric tensions developed during the hydrothermal swelling of rat skin. Connect Tissue Res 1980;7:127–133.
  10. Brinkmann R, Radt B, Flamm C, Kampmeier J, Koop N, Birngruber R: Influence of temperature and time on thermally induced forces in corneal collagen and the effect on laser thermokeratoplasty. J Cataract Refract Surg 2000;26:744–754.
  11. Moran K, Anderson P, Hutcheson J, Flock S: Thermally induced shrinkage of joint capsule. Clin Orthop 2000;381:248–255.

    External Resources

  12. Naseef GS III, Foster TE, Trauner K, Solhpour S, Anderson RR, Zarins B: The thermal properties of bovine joint capsule: The basic science of laser- and radiofrequency-induced capsular shrinkage. Am J Sports Med 1997;25:670–674.
  13. Vangsness CT, Mitchell W III, Nimni M, Erlich M, Saadat V, Schmotzer H: Collagen shortening: An experimental approach with heat. Clin Orthop 1997;337:267–271.

    External Resources



Pay-per-View Options
Direct payment This item at the regular price: USD 38.00
Payment from account With a Karger Pay-per-View account (down payment USD 150) you profit from a special rate for this and other single items.
This item at the discounted price: USD 26.50