title: Impact of Hydration Media on Ex Vivo Corneal Elasticity Measurements.
abstract: OBJECTIVE
  To determine the effect of hydration media on ex vivo corneal elasticity.
  
  
  METHODS
  Experiments were conducted on 40 porcine eyes retrieved from an abattoir (10 eyes each for phosphate-buffered saline (PBS), balanced salt solution, Optisol, 15% dextran). The epithelium was removed, and the cornea was excised with an intact scleral rim and placed in 20% dextran overnight to restore its physiological thickness. For each hydration media, corneas were evenly divided into two groups: one with an intact scleral rim and the other without. Corneas were mounted onto a custom chamber and immersed in a hydration medium for elasticity testing. Although in each medium, corneal elasticity measurements were performed for 2 hr: at 5-min intervals for the first 30 min and then 15-min intervals for the remaining 90 min. Elasticity testing was performed using nanoindentation with spherical indenters, and Young modulus was calculated using the Hertz model. Thickness measurements were taken before and after elasticity testing.
  
  
  RESULTS
  The percentage change in corneal thickness and elasticity was calculated for each hydration media group. Balanced salt solution, PBS, and Optisol showed an increase in thickness and Young moduli for corneas with and without an intact scleral rim. Fifteen percent dextran exhibited a dehydrating effect on corneal thickness and provided stable maintenance of corneal elasticity for both groups.
  
  
  CONCLUSIONS
  Hydration media affects the stability of corneal thickness and elasticity measurements over time. Fifteen percent dextran was most effective in maintaining corneal hydration and elasticity, followed by Optisol.
authors.affiliation: Biomedical Atomic Force Microscopy Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, FL.
authors.forename: Janice
authors.initials: J
authors.lastname: Dias
authors.forename: Noël M
authors.initials: NM
authors.lastname: Ziebarth
mesh_terms: D000818:Animals; D002809:Chondroitin Sulfates / Q000494:pharmacology*; D045424:Complex Mixtures / Q000494:pharmacology; D003315:Cornea / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D003911:Dextrans / Q000494:pharmacology*; D055119:Elastic Modulus / Q000502:physiology; D004548:Elasticity / Q000502:physiology*; D005839:Gentamicins / Q000494:pharmacology*; D009883:Ophthalmic Solutions / Q000494:pharmacology*; D013552:Swine
chemical_list: D045424:Complex Mixtures; D003911:Dextrans; D005839:Gentamicins; D009883:Ophthalmic Solutions; D002809:Chondroitin Sulfates; C075736:Optisol