Corneal cross-linking suitability criteria
Corneal cross-linking (CXL) is recommended for patients whose corneal scans show evidence of worsening keratoconus, or those who might be at especially high risk of worsening keratoconus. Progression of keratoconus usually stops by the mid-30s, so is not normally required for older patients.
How corneal cross-linking works
Healthy corneas are able to retain their shape due to strong bonds (cross-linkage) between collagen fibers. When keratoconus occurs, these cross links, or support beams, break down, weakening the cornea and causing the tissue to bulge outwards. Corneal cross-linking uses riboflavin eye drops and ultraviolet light to increase the amount and strength of the collagen bonds, therefore strengthening the cornea and preventing further loss of vision.
Advantages and disadvantages
- Improved vision: Up to 81% of patients who undergo CXL will be able to see more clearly after treatment.
- Minimally invasive: As opposed to a corneal transplant, which requires a surgical procedure, CXL is minimally invasive.
- Long-lasting results: Studies have concluded that the results of CXL can last for years and that the strengthening effect may be permanent.
- Shorter recovery: Recovery following a corneal transplant can often be a lengthy process. In contrast, CXL allows patients to return to normal activities within days.
In general, cross-linking is very safe, but you should allow time for your eye to heal and problems do occasionally occur. About 3% of patients will experience some loss of vision in the treated eye as a result of haze, infection or other complications. In most cases, we can reverse any visual loss with a corneal transplant. Without cross-linking treatment, at least 20% of all patients with keratoconus will eventually require a corneal transplant.
Corneal cross-linking risks
In general, CXL is very safe, but like all operations, your eye needs time to heal, and problems do occasionally occur. About 3% of patients will lose some vision in the treated eye as a result of haze, scarring, corneal surface shape irregularity or infection. In most cases, this visual loss is potentially reversible with a corneal transplant. Without CXL treatment, at least 20% of all patients with keratoconus will eventually require a corneal transplant. The risk of transplantation for patients with documented disease progression is probably higher.
Options and alternatives
We can combine cross-linking with intracorneal or intrastromal rings to flatten the keratoconus bulge even more. The rings stabilise keratoconus which prevents it from getting worse.
Corneal cross-linking steps
Step 1: We numb the surface of the eye, so you feel no pain.
Step 2: We remove the epithelial cell layer from the central part of the cornea, and apply the riboflavin eye drops.
Step 3: Once the eye drops have penetrated the cornea, we focus the UV light onto the central area of the cornea for 10 minutes.
Step 4: Finally, a bandage soft contact lens is applied. The contact lens is worn for up to 2 weeks until the surface epithelial cell layer has regrown.
Corneal cross-linking results
Cross-linking is currently the only available treatment which appears to stop the worsening of keratoconus.
Clinical trials based on outcomes one year after cross-linking show success in the halting of keratoconus in more than 90% of treated eyes, with more than 45% of eyes also gaining an improvement in corneal shape. A separate study over five years showed a similar success rate in halting the progress of keratoconus.
Visual improvement after treatment occurs in approximately 50% of cases. However, after treatment, you will still need to wear spectacles or contact lenses.