One new development in collagen cross-linking technology is a method that uses green light to activate rose bengal, a well-known diagnostic agent for ocular surface damage. This technology has already proven useful in sealing cornea wounds, bonding amniotic membrane to the corneal surface, and for applications in many other tissues [1-6]. Photochemical cross-linking of the corneal stroma using rose bengal and green light (a process referred to as RGX) has been shown to produce a similar increase in rabbit corneal stiffness to that achieved with riboflavin/UVA cross-linking. However, in contrast to riboflavin/UVA cross-linking which causes apoptotic cell death at depths up to 350 µm, RGX is limited to the anterior 100 µm of the tissue and is non-toxic to stromal keratocytes [7, 8]. Reconstructed bio-mechanical parameters from numerical finite element simulations show that the cross-linked layer of the cornea is actually stiffer after RGX than after riboflavin/UVA cross-linking. However, the cross-linked layer is substantially thinner after RGX and air puff deformation imaging of rabbit eyes indicate that the overall corneal stiffening effect achieved with RGX does not match that of riboflavin/UVA cross-linking .
Preliminary studies on rabbit corneas indicate that RGX has the potential to offer a rapid (less than 15 min), safe and effective treatment for ectatic diseases but further studies are needed to assess its safety in terms of the retina and iris.
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