Normal corneas have crosslinks between its collagen fibers that keep it strong and able to retain its normal shape. In keratoconus, the cornea is weak with too few cross-links or support beams. This weakened structure allows the cornea to bulge outwards. The cross-linking procedure adds cross-links or “cross beams” to the cornea, making it more stable, holding its shape and improving its focusing power. These new cross-links help strengthen the cornea and stops the thinning process and further loss of vision.
The treatment is recommended only for patients whose corneal shape scans show that their keratoconus is getting worse, or for those who are at particularly high risk of worsening keratoconus. Because of natural cross-linking with age, keratoconus usually stops getting worse by the mid-30s, so CXL is not normally required for older patients.
While the treatment will not correct vision or eliminate the need for glasses and/or contact lenses, it can help maintain the current level of vision and is meant to prevent vision from further worsening. Many research studies have shown that CXL may prevent further vision loss in over 95% of patients and improves vision in 60-81% of patients treated. It can also help those that cannot wear contact lenses to more easily fit into them.