Transepithelial Diluted Alcohol and Iontophoresis-Assisted Corneal Crosslinking for Progressive Keratoconus in Adults: 4-Year Clinical Results

A Review of Keratoconus Cross-Linking Treatment Methods

Corneal collagen cross-linking (CXL) is a therapeutic intervention that utilizes riboflavin photochemical activation with ultraviolet-A (UV-A) light to induce covalent cross-links within the stromal corneal fibers, effectively increasing corneal biomechanical stability and halting the progressive ectasia. The method was introduced in the late 1990s in Germany at the University of Dresden. The cross-linking method using the Avedro system (Waltham, MA, USA) was approved by the US Food and Drug Administration (FDA) on 18 April 2016, based on three prospective, multicenter, randomized clinical trials for keratoconus and other corneal ectasias. Recent innovations in CXL include a range of new treatment protocols and methods, which have been introduced to further enhance the clinical effectiveness, efficiency, and safety of CXL. These modifications encompass approaches like transepithelial or epithelium-on CXL (TE-CXL or epi-on CXL), accelerated CXL (ACXL), pulsed CXL (PL-CXL), transepithelial iontophoresis-assisted crosslinking (I-CXL), diluted alcohol and iontophoresis-assisted corneal cross-linking (DAI-CXL), slit-lamp CXL, and CXL plus (combined) methods. This review synthesizes findings on currently used modifications of the cross-linking method, the effectiveness, and directions of development of this currently dominant surgical method of treating corneal ectasia. This review concentrates on the long-term follow-up data, based on publications ranging from 1998 up to 2023.

Recent advances in medicinal compounds related to corneal crosslinking

Corneal crosslinking (CXL) is the recognized technique to strengthen corneal collagen fibers through photodynamic reaction, aiming to halt progressive and irregular changes in corneal shape. CXL has greatly changed the treatment for keratoconus (KCN) since it was introduced in the late 1990's. Numerous improvements of CXL have been made during its developing course of more than 20 years. CXL involves quite a lot of materials, including crosslinking agents, enhancers, and supplements. A general summary of existing common crosslinking agents, enhancers, and supplements helps give a more comprehensive picture of CXL. Either innovative use of existing materials or research and development of new materials will further improve the safety, effectiveness, stability, and general applicability of CXL, and finally benefit the patients.