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The structural response of the cornea to changes in stromal hydration

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


  • Sally Hayes, Cardiff University
  • ,
  • Tomas White, Cardiff University
  • ,
  • Craig Boote, Cardiff University
  • ,
  • Christina S Kamma-Lorger, ALBA Synchrotron Light Source
  • ,
  • James Bell, Cardiff University
  • ,
  • Thomas Sorenson
  • Nick Terrill, Diamond Light Source Ltd, Diamond House, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
  • ,
  • Olga Shebanova, Diamond Light Source Ltd, Diamond House, Harwell Science & Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
  • ,
  • Keith M Meek, Cardiff University

The primary aim of this study was to quantify the relationship between corneal structure and hydration in humans and pigs. X-ray scattering data were collected from human and porcine corneas equilibrated with polyethylene glycol (PEG) to varying levels of hydration, to obtain measurements of collagen fibril diameter, interfibrillar spacing (IFS) and intermolecular spacing. Both species showed a strong positive linear correlation between hydration and IFS2 and a nonlinear, bi-phasic relationship between hydration and fibril diameter, whereby fibril diameter increased up to approximately physiological hydration, H = 3.0, with little change thereafter. Above H = 3.0, porcine corneas exhibited a larger fibril diameter than human corneas (p < 0.001). Intermolecular spacing also varied with hydration in a bi-phasic manner but reached a maximum value at a lower hydration (H = 1.5) than fibril diameter. Human corneas displayed a higher intermolecular spacing than porcine corneas at all hydrations (p < 0.0001). Human and porcine corneas required a similar PEG concentration to reach physiological hydration, suggesting that the total fixed charge that gives rise to the swelling pressure is the same. The difference in their structural responses to hydration can be explained by variations in molecular cross-linking and intra/interfibrillar water partitioning.

Original languageEnglish
JournalJournal of the Royal Society. Interface
Publication statusPublished - Jun 2017
Externally publishedYes

    Research areas

  • Animals, Cattle, Corneal Stroma/physiology, Humans, Polyethylene Glycols, Sheep, Species Specificity, Swine, Water/metabolism

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ID: 142001108