Corneal collagen cross-linking (CXL) is a highly effective, evidence-based treatment designed to halt the progression of keratoconus and other corneal ectatic disorders. Unlike treatments that merely correct vision, cross-linking strengthens the corneal structure itself by increasing the bonding between collagen fibers, thereby stabilizing the cornea and preventing further thinning and deformation.

Keratoconus causes the cornea to progressively thin and bulge outward, leading to irregular astigmatism and distorted vision. If left untreated, the condition can progress to severe visual impairment requiring corneal transplantation. Corneal cross-linking is most effective when performed early, before advanced scarring or extreme thinning occurs.

The procedure involves the application of riboflavin (vitamin B2) eye drops to the cornea, followed by controlled exposure to ultraviolet-A (UV-A) light. This interaction triggers a photochemical reaction that strengthens corneal collagen bonds. There are two primary techniques: epithelium-off (standard) cross-linking, where the corneal surface layer is removed to allow better penetration of riboflavin, and epithelium-on (accelerated or transepithelial) cross-linking, which preserves the surface layer and may offer faster recovery in selected patients.

Corneal cross-linking is typically performed as a day-care procedure under topical anesthesia. While the treatment itself is painless, patients may experience temporary discomfort, light sensitivity, and blurred vision during the healing phase. Vision stabilizes gradually over weeks to months as the cornea heals and strengthens.

The primary goal of cross-linking is to stop disease progression rather than improve vision, although some patients experience mild visual improvement over time. Continued use of glasses or contact lenses may still be required. Regular follow-up with corneal imaging is essential to monitor long-term stability.

Corneal cross-linking has dramatically changed the management of keratoconus by reducing the need for corneal transplantation and preserving functional vision. When integrated into a structured keratoconus care pathway, it offers patients long-term corneal stability and improved quality of life.