Corneal cross-linking has been approved to treat keratoconus. Specifically, the Photrexa Viscous (riboflavin 5’-phosphate in 20% dextran ophthalmic solution) 0.146%, Photrexa (riboflavin 5’-phosphate ophthalmic solution) 0.146%, and the KXL system were the modality that was approved. This procedure has been used successfully in Europe and other countries for some time now, and we’ve been looking forward to it receiving FDA approval in the United States.
The way the procedure works is first the epithelium of the cornea is removed, riboflavin drops are put in the eye to saturate the corneal stroma (see diagram), then the corneal stroma is exposed to controlled ultraviolet light. This process causes linkages to be formed within the corneal stroma which make it more rigid and resistant to the changes in shape that cause loss of visual acuity in keratoconus.
This is big news for our patients with keratoconus because, while this treatment does not restore the cornea to its original structure, it has been shown to keep changes in the cornea due to keratoconus from progressing. Since it is this change in the corneal shape that distorts vision and reduces visual acuity, halting this progression allows someone with this condition to continue using special contact lenses such as hybrid or scleral contacts to see well and avoid having the condition progress to the point where corneal transplantation for keratoconus becomes necessary. If corneal changes are diagnosed early enough and corneal cross-linking is performed soon after diagnosis, vision may even remain correctable with regular eyeglasses, and scleral contact lenses may not be necessary.