Crosslinking treatment of keratoconus

Definition of keratoconus

Keratoconus is a degenerative disorder which affects the cornea. As the disease progresses, the shape of the cornea becomes more conical due to structural changes in the internal tissue. The main anatomical signs of keratoconus are a thinning of the cornea in an area in the central or adjacent areas almost always accompanied by the same area becoming raised causing high levels of irregular astigmatism, which leads to distorted vision.

What is corneal collagen crosslinking?

This is a process in which new links, or bonds, are generated between the chains of corneal collagen present in the tissue that has been affected by keratoconus.

The process consists of saturating the tissue with a substance called riboflavin that reacts with the collagen. Next, the creation of the new bonds between the long strands of collagen is activated by exposure to a light source in the ultraviolet range with a specific wavelength (UVA 375 nm). The energy delivered (3 mW/cm2) is carefully controlled by maintaining the light source at a predetermined distance for a specified period of time (30 minutes).

¿ What happens during the surgical procedure?

The procedure is carried out with the patient lying down, lightly sedated and using a local anaesthetic. After numbing the eye with anaesthetic eye drops, a thin layer of the corneal epithelium is removed so that the riboflavin can penetrate the stroma.

Several applications of the riboflavin solution are administered to the corneal tissue until the necessary saturation point has been reached. Next, the cornea is exposed to the appropriate source of energy for crosslinking to occur.

The riboflavin solution is applied every five minutes while the exposure to ultraviolet light continues for a total of 30 minutes.