Cross-Linking Science

Corneal collagen cross-linking is a medical procedure that combines the use of ultra-violet light and riboflavin eye drops. The procedure was first developed by Dr. Theo Seiler, Dr. Eberhard Spoerl and Dr. Gregor Wollensak in the late-1990s as a means of stabilizing the cornea to limit the progression of keratoconus1 and has been widely adopted as a conservative treatment for the condition as well as for iatrogenic ectasia.

Avedro-7771Standard Cross-Linking Procedure

Total treatment time = 60 minutes

  1. Riboflavin (vitamin B2) drops are applied to the cornea (30 minute riboflavin pre-soak)
  2. The cornea is exposed to ultra violet light (30 minute irradiation with 3mW/cm2 365nm UVA)
  3. The light causes the riboflavin to fluoresce, leading to the formation of bonds between collagen molecules or collagen cross-linking

Accelerated Cross-Linking Procedure

Total treatment time = 14 minutes or less

    1. Riboflavin (vitamin B2) drops are applied to the cornea (10 minute riboflavin pre-soak)
    2. The cornea is exposed to ultra violet light (4 minute irradiation with 30mW/cm2 365nm UVA)
    3. The light causes the riboflavin to fluoresce, leading to the formation of bonds between collagen molecules or collagen cross-linking2

The ophthalmology community has recently seen a marked increase in the prominence of corneal collagen cross-linking as a treatment strategy for progressive keratoconus and post-LASIK ectasia.As a first-line treatment, the greatest aim of cross-linking is to reduce and stop keratoconus progression in the early phase of the condition. This interest has arisen from a body of evidence documenting the biomechanical and cellular changes induced by cross-linking. The findings of this research provide a rationale for its use in keratoconus to halt the progression of the disease. A rapidly growing number of clinical publications suggest a consistent stabilizing effect of cross-linking along with a variable improvement in corneal shape and visual function in some patients. As a first-line treatment, the greatest aim of cross-linking is to reduce and stop keratoconus progression in the early phase of the condition, and to treat the progressive vision loss the condition may cause, potentially leading to corneal transplantation.

 

Avedro’s cross-linking systems and family of riboflavin products are not for sale in the US. MA-00313A

  1. Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a–induced collagen crosslinking for the treatment of keratoconus. Am. J. Ophthalmol. 2003;135(5):620–627.
  2. Touboul D, Efron N, Smadja D, Praud D, Malet F, Colin J. Corneal Confocal Microscopy Following Conventional, Transepithelial, and Accelerated Corneal Collagen Cross-linking Procedures for Keratoconus. J. Refract. Surg. 2012;28(11):769–776; Gatzioufas Z, Richoz O, Brugnoli E, Hafezi F. Safety Profile of High-Fluence Corneal Collagen Cross-Linking for Progressive Keratoconus: Preliminary Results From a Prospective Cohort Study. J. Refract. Surg. 2013;xx(x):1–3; Kanellopoulos AJ. Long term results of a prospective randomized bilateral eye comparison trial of higher fluence, shorter duration ultraviolet A radiation, and riboflavin collagen cross linking for progressive keratoconus. Clin. Ophthalmol. 2012;6:97–101.
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