CXL
Corneal Cross Linking – CXL
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The main body of the cornea is made up of parallel collagen fibres which rely on fibres linking across them to add strength to the structure. Without these links, the collagen fibres would slip and slide across each other and the cornea would be very weak. In normal eyes, the cornea is strong and withstands eye rubbing and lifting heavy weights (where the internal eye pressure goes up quite rapidly) quite easily.
In keratoconus and related conditions, these cross linking fibres are fewer in number than in normal corneas resulting in a weakened structure. Thus the cornea gives way to the internal pressure of the eye, resulting in “bulging” of some areas of the cornea. CXL is based on a biochemical reaction already well known to science. Riboflavin (Vitamin B2) drops are instilled into the eye until they have penetrated through the cornea. The eye is then irradiated with UVA light which leads to destabilisation of the riboflavin molecules and the production of oxygen free radicals. The riboflavin restabilises by linking with adjacent collagen fibrils thus forming a cross-link between them. This linking causes an increase in strength of the cornea which has been shown to halt the progression of keratoconus and related conditions over a period of several years. |
