Via National Keratoconus Foundation

Corneal collagen cross-linking (CXL) has been shown to be an efficient treatment option to slow or halt the progression of keratoconus. As the US keratoconus community waits patiently (?) for FDA approval of basic corneal crosslinking, researchers in other countries are exploring advanced variations to improve this procedure.

In biological and chemical sciences, crosslinking refers to new chemical bonds formed between reactive molecules. The aim of CXL is to synthetically increase the formation of crosslinks between collagen fibrils in the corneal stroma. While the efficiency of the conventional corneal crosslinking (CXL or C-CXL) protocol has already been shown in clinical studies, it might benefit from improvements in duration of the procedure and removal of corneal epithelium.

In order to provide a coherent evaluation of two new and optimized CXL protocols, researchers in Paris, France studied keratoconus patients who had undergone one of the three CXL treatments:

iontophoresis (I-CXL),

accelerated CXL (A-CXL),

and conventional CXL (C-CXL).
Accelerated crosslinking (A-CXL) is a 6 time faster CXL procedure using a ten time higher UVA irradiance but still including an epithelium removal. Iontophoresis (A-CXL) is a 6 time faster CXL procedure using a ten time higher UVA irradiance but still including an epithelium removal. Iontophoresis (I-CXL) is a transepithelial, non-invasive technique in which a small electric current is applied to improve riboflavin penetration throughout the cornea. Using anterior segment optical coherence tomography (AS OCT) and in vivo confocal microscopy (IVCM), it was conclude that regarding the depth of treatment penetration, conventional CXL protocol remains the standard for treating progressive keratoconus. Accelerated CXL ( A-CXL) seems to be a quick, effective and safe alternative to treat thin corneas. The use of iontophoresis is still being investigated and should be considered with greater caution.
SOURCE: Three Different Protocols of Corneal Collagen Crosslinking in Keratoconus: Conventional, Accelerated and Iontophoresis by Bouheraoua N, Jouve L, Borderie V, Laroche L.Quinze-Vingts National Ophthalmology Hospital; INSERM UMR S 968, Institut de la Vision; Sorbonne Universités, UPMC Univ Paris 06; CNRS, UMR 7210Quinze-Vingts National Ophthalmology Hospital; INSERM UMR S 968, Institut de la Vision; Sorbonne Universités, Pierre and Marie Curie UniversityUniv Paris