title: Reduction of stromal swelling pressure after UVA-riboflavin cross-linking.
abstract: OBJECTIVE
  We evaluated whether UVA-riboflavin collagen cross-linking (CXL) reduces stromal swelling pressure (SP) in porcine and human corneas ex vivo.
  
  
  METHODS
  Porcine corneas (N = 35) were divided into five groups: Full-thickness buttons, riboflavin-treated buttons, CXL-treated buttons, riboflavin-treated anterior and posterior lamellae, and CXL-treated anterior and posterior lamellae. Riboflavin- or CXL-treated human corneas (n = 6) were cut into anterior and posterior lamellae. The force exerted by the specimens during swelling in saline was recorded and SP was calculated. Dry weights were obtained for solids correction.
  
  
  RESULTS
  In full-thickness porcine buttons, a significantly reduced SP was observed after CXL (40.07 ± 3.86 mm Hg) compared to riboflavin treatment (68.13 ± 11.39 mm Hg, P = 0.02) at 5% compression. Also, a trend toward reduced SP in the CXL-treated anterior human lamellae (9.9 mm Hg) was found compared to the riboflavin group (25 mm Hg) at 5% compression. In the anterior porcine lamellae a significant SP reduction was observed in the CXL group versus the riboflavin group (P < 0.001, two-way ANOVA). Likewise, in the posterior porcine lamellae, a significant SP reduction was observed in the CXL group versus riboflavin alone (P < 0.05, two-way ANOVA). Posterior human lamellae did not differ in SP when comparing CXL and riboflavin groups.
  
  
  CONCLUSIONS
  Our study demonstrated a significant reduction in anterior stromal SP in porcine and human corneas after CXL. This finding suggested that CXL may reduce corneal SP in vivo, and thereby reduce edema and improve vision. Thus, in the clinical setting, patients suffering from corneal edema may benefit from CXL treatment.
authors: Department of Ophthalmology, Aarhus University Hospital, Nørrebrogade 44, Aarhus C, Denmark. nders@soendergard.dk
authors: Anders P
authors: AP
authors: Søndergaard
authors: Anders
authors: A
authors: Ivarsen
authors: Jesper
authors: J
authors: Hjortdal
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003094:Collagen / Q000494:pharmacology; D015715:Corneal Edema / Q000473:pathology / Q000628:therapy*; D003319:Corneal Stroma / Q000473:pathology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004728:Endothelium, Corneal / Q000473:pathology; D005486:Flavin Mononucleotide / Q000494:pharmacology*; D006801:Humans; D013552:Swine; D014466:Ultraviolet Rays; D014803:Vitamin B Complex / Q000494:pharmacology*
chemical_list: D003432:Cross-Linking Reagents; D014803:Vitamin B Complex; D005486:Flavin Mononucleotide; D003094:Collagen