RT Journal Article T1 Epithelium-Off vs. transepithelial corneal collagen crosslinking in progressive keratoconus: 3 years of follow-up A1 Arance Gil, Ángeles A1 Villa Collar, César A1 Pérez Sánchez, Belén A1 Carracedo Rodríguez, Juan Gonzalo A1 Gutiérrez Ortega, Ángel Ramón AB Purpose: To compare the efficacy of epithelium-off corneal collagen crosslinking (CXL) with transepithelial CXL in patients with progressive keratoconus with a follow-up of 3 years, taking into account the patients’ age and the location of the corneal ectasia.Methods: In this prospective study participated 64 eyes with progressive keratoconus were included in this long-term study, of which 31 eyes were treated by epithelium-off CXL and 33 by transepithelial CXL. All of the patients with a follow-up of 36 months were evaluated for visual variables (corrected distance visual acuity (CDVA), corneal aberrations, and corneal densitometry), structure variables (astigmatism, keratometry, corneal asphericity, maximum posterior elevation, corneal thickness, and corneal volume), and keratoconus index variables.Results: After corneal CXL, CDVA improved significantly in both central and paracentral keratoconus, with greater improvement in the centrals (p = 0.001), asphericity at 6 mm improved in central keratoconus (p = 0.047). In the epi-off group, there was a significant improvement in coma-like (p = 0.038), higher-order aberrations (p = 0.036), asphericity at 8 mm (p = 0.049), asphericity at 10 mm (p = 0.049), and index of surface variance (p = 0.049).Conclusion: Although both techniques halted and stabilized the progression of keratoconus, epithelium-off CXL was more effective. In addition, after the corneal CXL, there was a greater degree of regularization of the corneal surface and, therefore, a greater improvement in the CDVA with central keratoconus than with paracentral keratoconus. PB Spanish General Council of Optometrists SN 1888-4296 YR 2020 FD 2020-09-01 LK https://hdl.handle.net/20.500.14352/6532 UL https://hdl.handle.net/20.500.14352/6532 LA eng NO En OA en la web del editor.Received 25 November 2019, Accepted 15 July 2020, Available online 1 September 2020. DS Docta Complutense RD 16 abr 2025