Trans-epithelial osmotic collyrium for the treatment of keratoconus by corneal cross-linking with UV rays, of the type consisting of a riboflavin-based solution and an absorption enhancement adjuvant consisting of benzalkonium chloryde (BAC). The solution has a hypoosmolarity degree ranging between −70% and −30% over an isotonic solution and contains a BAC concentration accordingly ranging between 0.005% and 0.035%.
