Changes in the biomechanical properties of the human cornea play an important role in the pathogenesis of corneal ectatic diseases. Many different pathological conditions in the cornea may reduce its biomechanical resistance. Corneal collagen cross-linking (CXL) has emerged as a promising technique to slow or even to stop the progression of ectasia. In this procedure, riboflavin (vitamin B2) is administered in conjunction with ultraviolet A light (UVA, 365 nm). This interaction causes the formation of reactive oxygen species, leading to additional covalent bonds between collagen molecules, with consequent biomechanical stiffening of the cornea. Although this method is not yet accepted as an evidence-based treatment of corneal ectasia, the results of prospective, randomised studies of CXL used in the treatment of this pathological entity show significant changes in the properties of corneal tissue. This procedure is currently the only aetiopathogenetic treatment of ectatic eyes that can delay or stop the process of cornea destabilisation, reducing the necessity for keratoplasty. Despite promising results, CXL is associated with issues that include long-term safety and duration of the stabilising effect.
- MeSH
- Photochemotherapy methods MeSH
- Photosensitizing Agents administration & dosage MeSH
- Keratoconus drug therapy MeSH
- Humans MeSH
- Evidence-Based Medicine MeSH
- Cross-Linking Reagents radiation effects MeSH
- Riboflavin administration & dosage MeSH
- Cornea drug effects radiation effects MeSH
- Ultraviolet Therapy methods MeSH
- Treatment Outcome MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Corneal cross-linking can halt the progression of keratoconus, but what is the best approach for treatment? There are a number of treatment options for keratoconus, but only corneal cross-linking (CXL) appears to halt the progression of the disease. To guarantee effective cross-linking, CXL treatment involves removal of the corneal epithelium prior to riboflavin application and ultraviolet light illumination - "epi-off" CXL. Several methods of "epi-on" (transepithelial) CXL have been proposed, such as keeping the corneal epithelium intact which should be less painful and help avoid other CXL-associated adverse events. The evidence so far is that epi-off CXL remains the most effective method of strengthening the cornea and slowing keratoconus progression - but transepithelial methods are gaining ground.
- MeSH
- Photochemotherapy methods MeSH
- Photosensitizing Agents administration & dosage MeSH
- Keratoconus pathology therapy MeSH
- Combined Modality Therapy methods MeSH
- Humans MeSH
- Evidence-Based Medicine MeSH
- Cross-Linking Reagents administration & dosage MeSH
- Riboflavin administration & dosage MeSH
- Epithelium, Corneal surgery MeSH
- Ultraviolet Therapy methods MeSH
- Treatment Outcome MeSH
- Check Tag
- Humans MeSH
- Publication type
- English Abstract MeSH
- Journal Article MeSH
- Review MeSH
PURPOSE: To analyze the 10-year results of corneal collagen crosslinking (CXL) for keratoconus. SETTING: Department of Ophthalmology, University Hospital, Dresden, Germany. DESIGN: Retrospective interventional case series. METHODS: The study included eyes treated for progressive keratoconus from 2000 to 2004. Corneal collagen crosslinking was performed by applying riboflavin and ultraviolet-A. The corrected distance visual acuity (CDVA), corneal topography, and endothelial cell count (ECC) were recorded preoperatively and 10 years postoperatively. RESULTS: The study enrolled 24 patients (34 eyes). The mean age of the 18 men and 6 women was 28.4 years ± 7.3 (SD) and the mean follow-up, 131.9 ± 20.1 months. The mean apical keratometry (K) value was 61.5 diopters (D) preoperatively and 55.3 D 10 years postoperatively; the decrease was statistically significant (P<.001). The mean values for maximum K (53.2 D and 49.56 D, respectively) and minimum K (47.5 D and 45.5 D, respectively) were also significantly lower (P<.001). The preoperative and postoperative CDVA were statistically significantly different (P=.002). The mean CDVA improved by 0.14 logMAR over preoperatively; the change was statistically significant (P=.002). The ECC was unchanged. CONCLUSIONS: Corneal CXL was effective in treating progressive keratoconus, achieving long-term stabilization of the condition. It was easy to perform, had a good safety profile, and reduced the need for corneal transplantation. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
- MeSH
- Adult MeSH
- Photochemotherapy * MeSH
- Photosensitizing Agents adverse effects therapeutic use MeSH
- Keratoconus drug therapy metabolism physiopathology MeSH
- Collagen metabolism MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Follow-Up Studies MeSH
- Disease Progression MeSH
- Cross-Linking Reagents * MeSH
- Retrospective Studies MeSH
- Riboflavin adverse effects therapeutic use MeSH
- Corneal Stroma metabolism MeSH
- Ultraviolet Rays MeSH
- Visual Acuity physiology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- MeSH
- Biomechanical Phenomena MeSH
- Animal Experimentation MeSH
- Formaldehyde analogs & derivatives therapeutic use MeSH
- Photochemotherapy methods adverse effects MeSH
- Glutaral therapeutic use MeSH
- Keratoconus prevention & control therapy MeSH
- Rabbits MeSH
- Keratomileusis, Laser In Situ adverse effects MeSH
- Humans MeSH
- Ophthalmologic Surgical Procedures methods instrumentation adverse effects MeSH
- Swine MeSH
- Riboflavin therapeutic use MeSH
- Corneal Topography utilization MeSH
- Corneal Stroma anatomy & histology radiation effects MeSH
- In Vitro Techniques MeSH
- Ultraviolet Therapy methods adverse effects MeSH
- Check Tag
- Rabbits MeSH
- Humans MeSH
