title: [Is viscoelastic the corneal tissue?].
abstract: OBJECTIVE
  To compare the known viscoelastic properties of soft tissues with singular published observations on the behaviour of corneal tissue.
  
  
  METHODS
  The behaviour of the maxwellian element, typical viscoelastic biomechanical model, is compared with that of various previously studied soft tissues of animals. The same comparison can be made between stress-strain curves of riboflavin and UVA treated and untreated strips of human and porcine corneal tissue, stretched at constant velocity, from the literature.
  
  
  RESULTS
  The asymptotic stress-strain curves of the various soft tissues previously examined could be faithfully simulated by the Maxwell viscoelastic element. The exponential stress-strain curves of samples of corneal tissue were clearly different.
  
  
  CONCLUSIONS
  The observed divergence demonstrates incompatibility between the alleged behaviour of corneal tissue and the viscoelastic properties attributed to it. Thus there are two possibilities: either corneal tissue is viscoelastic and the experiment showing exponential behaviour suffers from some technical problem, or the data is correct and corneal tissue is not viscoelastic. In either case further research is necessary for correct interpretation of the mechanism of cross-linking and for consequent therapeutic choices.
authors.affiliation: Fisica Medica, Dipartimento di Fisica, Università di Siena, Italia. albanesea@unisi.it
authors.forename: A
authors.initials: A
authors.lastname: Albanese
authors.forename: E
authors.initials: E
authors.lastname: Battisti
authors.forename: G M
authors.initials: GM
authors.lastname: Galassi
authors.forename: R
authors.initials: R
authors.lastname: Urso
authors.forename: L
authors.initials: L
authors.lastname: Bianciardi
authors.forename: M
authors.initials: M
authors.lastname: Rigato
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003094:Collagen / Q000187:drug effects / Q000648:ultrastructure; D003315:Cornea / Q000187:drug effects / Q000502:physiology*; D003432:Cross-Linking Reagents / Q000494:pharmacology / Q000528:radiation effects; D004548:Elasticity; D006801:Humans; D012256:Riboflavin / Q000494:pharmacology / Q000528:radiation effects; D013314:Stress, Mechanical; D034421:Sus scrofa; D013552:Swine; D014466:Ultraviolet Rays; D014783:Viscosity
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen; D012256:Riboflavin