1. SIMAR J. SINGH 1, WILLIAM B. TRATTLER 1,2, GABRIELA PEREZ 2, DAVID T. LIN 3 1 Herbert Wertheim College of Medicine, Florida International University, Miami FL 2 Center for Excellence in Eye Care, Miami FL 3 University of British Columbia, Vancouver BC Dr. Trattler has received funding for research, consulting and/or speaking from: CXLUSA

2. Purpose and Methods Purpose: To report the results of bilateral CXL followed by topography- guided PRK for a commercial airline pilot who required excellent uncorrected visual acuity to continue with his occupation. Methods: A 33-year-old African American male commercial airline pilot with advanced bilateral keratoconus & no previous ocular surgery was treated with epithelial-off CXL followed 4 months later by topography- guided PRK with the Allegretto laser platform. A comparison of UCVA, BCVA, pentacams, and placido-disk topographies were gathered pre & post CXL treatment and & post PRK.

3. Results ODPre OpPre PRK/ Post CXL Last Visit/ Post CXL and PRK UCVA200 40 BCVA504030 Refraction- 7.50+1.50x08 0 -8.00+0.75x105-3.75+0.50x55 OSPre OpPre PRK/ Post CXL Last Visit/ Post CXL and PRK UCVA4005025 BCVA30 25 Refraction- 5.75+1.50x100 -5.75+0.75x080-2.50+0.75x120

4. Difference Map OD: Pre-Op to Post-CXL/ Pre-PRK Post-CXL Pre-Op Difference Map 4 D Flatter

5. Difference Map OD: Pre-Op to Last Visit (Post-CXL and Post-PRK) Difference Map Pre-OpPost-CXL/ Post-PRK 11 D Flatter

6. Conclusions This case illustrates the potential for marked improvement in UCVA and BCVA in patients who have undergone CXL followed by topography- guided PRK. Patients with advanced keratoconus may experience greater improvement in visual acuity and experience a greater improvement in quality of vision with CXL followed by PRK when compared to CXL alone. KEYWORDS: Keratoconus, Corneal Crosslinking, Photorefractive keratectomy (PRK).