Standard Versus Transepithelial Corneal Crosslinking
Standard Versus Transepithelial Corneal Crosslinking for Treatment of Progressive Keratoconus
The gold standard corneal crosslinking (CXL) technique involves the initial step of epithelial removal, in order to achieve a sufficient treatment effect (meaning: stabilisation of progressive keratoconus (KC). Our aim is to evaluate the effects of transepithelial CXL (TE-CXL), whereby the epithelium is left intact and the cornea is instead treated by a solution composed of 0.1% riboflavin, combined with enhancers, after which standard CXL is performed. This solution seems to facilitate riboflavin penetration into the corneal stroma through the intact epithelium. The investigators expect to achieve a similar effect of TE-CXL with the advantage of a faster healing time and less risk of infections.
A comparison of the CXL procedure with and without epithelium removal
Ricrolin TE was instilled during 30 minutes before ultraviolet-A irradiation
After epithelium removal, isotonic riboflavin was instilled during 30 minutes before ultraviolet-A irradiation
epithelium removal + 30 minute isotonic riboflavin eye drops (3 minute interval) + 30 minutes ultraviolet-A irradiation (riboflavin every 5 minutes)
Inclusion Criteria: Documented progressive KC (by Pentacam and/or corneal topography imaging). A clear central cornea. A minimal corneal thickness of ≥ 400 µm at the thinnest corneal location (Pentacam imaging). Minimal Snellen corrected distance visual acuity of ≥ 0.4. Patient age of ≥ 18 years. For this research study, the inclusion parameters will be the same as mentioned above, with the following additional inclusion criteria: Documented progression of KC, as demonstrated by anterior segment imaging and/or corneal topography: o Defined an increase in maximal keratometry, steepest keratometry, mean keratometry or topographic cylinder value by ≥ 0.5 D over the previous 6 months and/or a decrease in thinnest pachymetry Documented progression of KC defined by increase in refractive cylinder of ≥ 0.5 D over the previous 6 months Exclusion Criteria: Presence of corneal scars. History of epithelial healing problems. Presence of previous ocular infection (such as herpes keratitis). Patients who are pregnant and/or breastfeeding.