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Untraviolet Riboflavin Collagen Crosslinking in Keratoconus – Initial Results J Brady, W Power, W Lee The Authors have no financial interetsts in the subject matter of this poster Royal Victoria Eye and Ear Hospital Dublin Ireland Introduction Keratoconus has an incidence of 1 in 2000 in the general population and up to now there has been no way to alter the disease course. In this new technique a photosensitizer (Riboflavin) is excited by UV light at 370nm into its triplet state generating reactive oxygen species (ROS). These ROS react with other molecules forming covalent bonds bridging amino groups of collagen fibrils (type II photochemical reaction). Animal studies have shown that the effect of crosslinking is to increase increase collagen rigidity, collagen fibre diameter with an associated resistance to collagenases. Purpose To evaluate the response of patients to ultraviolet riboflavin collagen crosslinking Study Design Retropective review of all keratoconus patients undergoing untraviolet riboflavin collagen crosslinking over a 12 months period. Inclusion Criteria Patients with keratonconus with proven progression on Scheimpflung imaging (Pentacam) carried out 6 months apart Surgical Technique •Sterile Procedure •Calibration of light source •Proxymethocaine Drops •Corneal Epithelium debrided using 20% alcohol in 7mm well for 30 seconds then manually removed •Pachymetry •Drops of 0.1% riboflavin onto cornea every 3 minutes for 30 mins onto cornea •UV light source focused on cornea for 30 more minutes while continuing with riboflavin drops to cornea – Irradiance 3 mW/cm2 •Rinse •C Chloromycetin minims and Bandage Contact Lens •Post op – strong analgesia, prednisolone phosphate QDS G chloramphenicol QDS G artelac SDU QDS Data Collection The following data was collected at preoperative assessment and at each followup visit: •Uncorrected and Corrected Visual Acuity •Keratometry •Refraction •Corneal Thicknesskness •Corneal Topography (pentacam) Results •To date 22 eyes of 16 patients with more than 12 months follow-up •Mean follow-up 13 months (range 12 – 18) Mean Preoperative Parameters •BSCVA 0.48 ± 0.19 (LogMar) Range 0.3 – 0.8 Conclusions Our results confirm those of earlier studies demonstrating a stabilisation of corneal parameters post treatment. •This minimally invasive, technically simple, once-off treatment is a promising new development in the stabilisation of keratoconus and other corneal ectasias. Further follow-up of our patient cohort will be required to assess its long-term effects. •Astigmatism 3.7 ± 1.98 Range 1.5 – 7.5 • 5: Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003 May;135(5):620-7. PubMed PMID: 12719068. 43.8 ± 2.9 Range 0.4 - 4 • 7: Wollensak G. Crosslinking treatment of progressive keratoconus: new hope. Curr Opin Ophthalmol. 2006 Aug;17(4):356-60. Review. PubMed PMID: 16900027. •K Max Postoperative Results •Reduction in K Max •Reduction in Mean Cyl References •1: Hafezi F, Mrochen M, Iseli HP, Seiler T. Collagen crosslinking with ultraviolet-A and hypoosmolar riboflavin solution in thin corneas. J Cataract Refract Surg. 2009 Apr;35(4):621-4. PubMed PMID: 19304080. •2: Micelli Ferrari T, Leozappa M, Lorusso M, Epifani E, Micelli Ferrari L. Escherichia coli keratitis treated with ultraviolet A/riboflavin corneal cross-linking: a case report. Eur J Ophthalmol. 2009 MarApr;19(2):295-7. PubMed PMID: 19253251. • 3: Wittig-Silva C, Whiting M, Lamoureux E, Lindsay RG, Sullivan LJ, Snibson GR. A randomized controlled trial of corneal collagen cross-linking in progressive keratoconus: preliminary results. J Refract Surg. 2008 Sep;24(7):S720-5. PubMed PMID: 18811118. • 4: Raiskup-Wolf F, Hoyer A, Spoerl E, Pillunat LE. Collagen crosslinking with riboflavin and ultraviolet-A light in keratoconus: long-term results. J Cataract Refract Surg. 2008 May;34(5):796-801. PubMed PMID: 18471635. • 6: Wollensak G, Wilsch M, Spoerl E, Seiler T. Collagen fiber diameter in the rabbit cornea after collagen crosslinking by riboflavin/UVA. Cornea. 2004 Jul;23(5):503-7. PubMed PMID: 15220736. Riboflavin 0.93 ± 0.79 Range (0 – 2.5) 1.34 D ± 1.15 Best Corrected cornea Visual Acuity •Improved by at least one line in 19/20 •No deterioration in BSCVA •Change in BSCVA 0.16 ± 0.12(LogMar) Riboflavin saturated corna Light source BSCVA and keratometry remained stable in all patients with no further progression of disease on Scheimpflung imaging. 3 MW/cm2