1. Ramon C. Ghanem, M.D. 1, 2 ; Vinícius C. Ghanem, M.D. 1, 2 ; Marcony Santhiago, M.D. 2,3 ; Marcelo V. Netto, M.D. 2,3 ; Steven E. Wilson, M.D. 3 1. Sadalla Amin Ghanem Eye Hospital, Joinville, Brazil. 2. University of São Paulo (USP), São Paulo, Brazil. 3. Cleveland Clinic, Cole Eye Institute, Ohio, USA

2. Financial Disclosures The authors do not have a commercial or proprietary interest in this work. RC. Ghanem, Poster WCC 2010 Purpose To report a case series of peripheral ring-shaped corneal infiltrates that occurred a few days after crosslinking (CXL) for progressive keratectasia secondary to keratoconus.

3. Methods A prospective study including 362 eyes with progressive keratoconus was carried out. After a 9.0 mm epithelial removal, 0.1% riboflavin with 20% dextran was applied for 30 minutes followed by ultraviolet-A (UVA) irradiation (370 nm, 3 mW/cm 2 ) 1. Therapeutic contact lenses were placed for one week. RC. Ghanem, Poster WCC 2010 1. Wollensak G, et al. AJO. 2003

4. Results Three eyes (0.8%) developed an unusual type of peripheral infiltrate. These had a ring-shape and affected the anterior stroma in the transition between the treated and untreated peripheral cornea a few days after treatment. RC. Ghanem, Poster WCC 2010

5. Case 1 25-year-old male 25-year-old male After 12 days of CXL After 12 days of CXL

6. Case 1 epithelial ulceration 360 degrees peripheral ring-like infiltrate at the 9.0-mm zone

7. Case 1 After 3 months After 3 months

8. Case 2 21-year-old male 21-year-old male A week after CXL A week after CXL

9. Case 3 24-year-old male 24-year-old male A week after CXL A week after CXL

10. RC. Ghanem, Poster WCC 2010 Preoperative DataPostoperative Data (3 Months) Age/Sex/E ye Dynamic Refraction DCVA * Biomicroscopy Max K** US Pachy Systemic Workout Biomicroscopy Dynamic Refraction DCVA* Max K** US Pachy Case 125/M/OD+2.0 -6.0 x 50°20/30 Vogt´s striae 1+, Fleisher´s ring, no blepharitis 58.5487Negative 360 degrees infiltrate in the anterior stroma, faint central haze +1.50 -6.0 x 50°20/3057.7446 Case 221/M/OD-0.25 -4.5 x 180°20/20 No blepharitis 46.3433Negative 180 degrees superficial infiltrate, no central haze N/A Case 324/M/OD-2.25 x 155°20/25 Two segments of Ferrara´s ring, no blepharitis 47.2441Negative Discrete inferior peripheral infiltrate, central haze 1+ -0.5 -0.5 x 150°20/3047.7436 Cases Sumary

11. Results All cases had rapid improvement with steroidal therapy. Due to its shape and location, occurring in the 9.0 mm edge of the irradiation zone with a limbal clear area, immune reaction seems to be the main explanation. We hypothesize that the cytotoxic effects of UVA irradiation during CXL may alter the antigenic sites on native proteins in the corneal stroma resulting in a localized autoimmune reaction. RC. Ghanem, Poster WCC 2010

12. Conclusion Peripheral sterile corneal infiltrates are not a rare complication after CXL. Although the exact mechanism is unclear, identification of this entity and its differentiation from infectious keratitis is essential. The inflammatory response of the UVA light irradiation during CXL and its role on the immune mechanisms of the cornea demand further investigation. RC. Ghanem, Poster WCC 2010 Thank you