ReviewEfficacy of Corneal Collagen Cross-Linking for the Treatment of Keratoconus A Systematic Review and Meta-AnalysisMeiri, Zohar BMedSc; Keren, Shay MD; Rosenblatt, Amir MD; Sarig, Tal MSc; Shenhav, Liat BSc; Varssano, David MDAuthor Information *Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; †Department of Ophthalmology, Tel Aviv-Sourasky Medical Center, Tel Aviv, Israel; and ‡Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel. Reprints: Shay Keren, MD, Department of Ophthalmology, Tel Aviv-Sourasky Medical Center, 6 Weitzman St, Tel Aviv 64239, Israel (e-mail: [email protected]). The authors have no funding or conflicts of interest to disclose. Z. Meiri and S. Keren contributed equally to this article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.corneajrnl.com). This work was performed in partial fulfillment of the MD thesis requirements of the Sackler Faculty of Medicine, Tel Aviv University (Z.M.). Received August 26, 2015 Received in revised form October 26, 2015 Accepted October 28, 2015 Cornea: March 2016 - Volume 35 - Issue 3 - p 417-428 doi: 10.1097/ICO.0000000000000723 Buy SDC Metrics Abstract Purpose: To examine the efficacy of corneal collagen cross-linking (CXL) for the treatment of keratoconus (KCN). Methods: A systemic literature review and meta-analysis of ocular functional and structural parameters of patients with KCN undergoing cross-linking procedures were performed using PubMed and the web of science. A literature search was performed for relevant peer-reviewed publications on population-based studies. Data were analyzed with R software (Meta library), and heterogeneity was assessed with the Cochran Q and I2. A random-effects model was used for high heterogeneity; otherwise a fixed model was used. Sensitivity analysis of particular tested groups was used to explain high heterogeneity. The main outcome measures extracted from the articles were corrected distance visual acuity, uncorrected distance visual acuity, and maximum K. Results: An improvement in visual acuity of 1 to 2 Snellen lines was found 3 months or more after undergoing CXL. Changes were more pronounced in uncorrected visual acuity. Some topography parameters were found to be improved (0.6–1 diopters) 12 to 24 months after CXL. The refractive cylinder improved by 0.4 to 0.7 diopters. Endothelial cell density decreased by 225 cells per square millimeter in the first 3 months and thereafter returned to normal. Corneal thickness was reduced by 10 to 20 μm in the year following CXL but not after 24 months. No changes in intraocular pressure were noted. Conclusions: CXL is a safe and effective method for halting the deterioration of KCN, while slightly improving visual function. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.