Evaluation of Efficiency and Security of Transepithelial Corneal Collagen Crosslinking With Oxygen to Treat Progressive Keratoconus.

Keratoconus is a common bilateral progressive corneal ectatic disease causing visual impairment by inducing irregular astigmatism and corneal opacities. This disorder typically begins during teenage years. Patients with severe forms may need a corneal transplantation. The CXL procedure, described in 1998, allows to halt or to slow down the disease progression and may avoid other surgeries, e.g. transplantation. This technique creates links between collagen fibrils in order to rigidify the corneal stroma. The corneal stroma is soaked with a riboflavin solution (vitamin B2) before being exposed to ultraviolet-A (UVA) radiations. In the current standard CXL, the central corneal epithelium must be debrided to allow the penetration of riboflavin into the cornea, with a risk of side effects, such as pain for the first two post-operative days, temporary loss of visual acuity during the first three months, and serious complications such as infections and stromal opacity due to corneal scarring Transepithelial crosslinking is a non-invasive technique in which benzalkonium chloride is used to enhance the penetration of riboflavin into the cornea. To improve the reaction, a device provides oxygen to the corneal surface. The transepithelial technique could allow intrastromal riboflavin diffusion, while keeping the corneal epithelium on, conserving the efficiency of the standard procedure without the complications induced by epithelial debridement.

Patient with progressive keratoconus will be included and treated with the transepithelial procedure. The follow-up will last for one year. Every follow-up visit will evaluate the security of the procedure and its efficacy to stop or slow down the progression of the disease. Interrogatory and slit lamp examination will be performed to investigate the potential adverse effects of the procedure.