Preoperative Corneal Measurements Estimate the Corrected Distance Visual Acuity After Corneal Cross-linking

Standard Dresden protocol corneal cross-linking procedure The CXL procedure adhered to the standard Dresden protocol. All patients received topical anaesthetic (Tetracaine HCL 0.5%, Alcon Forth Worth, Texas) and a miotic (Isopto Carpine 2% HCl, Alcon, Fort Worth, Texas) drops 30 minutes before the procedure. The periocular region and conjunctival sac were washed with 10% povidone-iodine (Betadine 10%, Alcaloid, Skopje). Manual epithelial scraping with a crescent knife followed. Pachymetry was kept over 400 μm during the procedure and measured with an ultrasound hand pachymeter (Pocket II, Quantel Medical, Cournon d'Auvergne, France). Riboflavin (Peschke D, Peschke Trade, Huenenberg, Switzerland) was applied every 3 minutes for 30 minutes. We performed corneal UV-A radiation with a wavelength of 370 nm and energy of 3mW using a UVA CXL lamp (VEGA CBM-X-Linker, Carleton Optical, Chesham, UK) for 30 minutes (6 cycles of 5 minutes each).