Crosslinking of Cornea using Accelerated C3R or KXL
Collagen Crosslinking (C3R) for keratoconus
- Is an out-patient procedure.
- It is performed under topical anaesthesia (eye drops).
- The skin of the eye (epithelium) is removed.
- Riboflavin eye-drops are applied to the cornea for 30 minutes.
- The eye is then bathed in a very specific wavelength of light-UVA for 30 minutes.
- The combination of the light and riboflavin causes chemical bonds to form within the cornea, increasing its rigidity and stability.
- The whole process traditionally takes about 90 minutes.
- A protective soft contact lens is worn for about 24 hours, and eye drops need to be instilled to limit the risk of infection and corneal haze.
What is Accelerated Crosslinking?
The accelerated crosslinking mirrors the above procedure above but differs and benefits patients in 3 ways:
- More importantly, accelerated crosslinking allows thinner corneas to be crosslinked with greater precision, potentially decreasing the risks associated for crosslinking. In effect those patients outside current treatment criteria can be crosslinked and receive the benefits.
- Reduces cross-linking time from one-hour to a few minutes, adding to patient comfort and experience.
- The new Riboflavin solutions can penetrate the epithelium and this procedure is called “Transepithelial Corneal Collagen Cross-linking”.
We use two systems:
- The UV-X™ Illumination System – a 30 minute Riboflavin soak time and then typically 30 minutes of UVA exposure – this takes about 1 hour in the theatre time
- The Avedro KXL® Accelerated Cross-Linking system- a 3-5 minute soak time and then typically 3 minutes of UVA exposure.
Both the procedures are extremely safe, and no sight-damaging complications have been reported.
This takes advantage of the combined action of riboflavin (vitamin B2) and UV-A rays, an action that strengthens the bonds between the collagen fibres in the corneal tissue, slowing down the progressive erosion of the corneal surface caused by keratoconus.
This technique, which, unlike the traditional technique, does not involve removal of the corneal epithelium – the thinnest layer on the outside of the cornea – before administering riboflavin eye drops and ultraviolet light. This renders the treatment completely pain-free not only during, but also after the procedure, with identical postoperative results, and guarantees the patient’s well-being.
C3-R treatment seems to be a valid option in order to postpone, and in the most fortunate cases, avoid corneal transplantation.
THE ACCELERATED CORNEAL CROSS-LINKING PROCEDURE AND ITS ADVANTAGES
During treatment a photosensitive preparation of vitamin B2 eye drops is applied to the cornea, which is then soaked for approx. 60 seconds. The ribolflavin is dynamized by UV-A rays generated by special equipment: this second step lasts 3 minutes, during which the riboflavin penetrates the corneal surface by a few microns and induces the lamellae to move closer together.
It is an outpatient procedure, non-invasive and painless, lasting for approximately five minutes per eye from start to finish. This is a remarkable improvement, if compared to the 30 minutes time span required to carry out a standard cross-linking procedure. Additionally, it has the advantage that it can be repeated at a later date.
A procedure called Lasik Xtra, which is designed to strengthen the cornea after LASIK, has received CE approval for marketing in the European Union. It was just approved in Canada as well.
Marketed by Avedro, Inc., Lasik Xtra is a corneal crosslinking procedure that applies the company’s VibeX riboflavin ophthalmic solution to the eye’s surface (cornea), and then uses Avedro’s KXL System to irradiate the cornea with UV-A rays. Lasik Xtra is an accelerated form of crosslinking which takes two minutes and makes it more convenient to combine with LASIK.