title: Effect of Trypan Blue on Descemet Membrane Elasticity.
abstract: OBJECTIVE
  To evaluate the effect of trypan blue on the elastic property of Descemet membrane (DM) by atomic force microscopy.
  
  
  METHODS
  Human corneas (n = 10) were obtained from the Illinois Eye Bank (Chicago, IL). The DM was isolated and divided into two halves, one half was stained with ophthalmic trypan blue (Vision Blue, 0.06%, DORC International), whereas the unstained other half served as control. The DM samples were then tested using the atomic force microscope. Data were analyzed using the Hertz model for the evaluation of the Young modulus of elasticity.
  
  
  RESULTS
  Atomic force microscopy showed higher cantilever deflection on trypan blue-stained DM compared with control, and the difference was statistically significant (P = 0.03). Force-distance curve analysis also revealed a statistically significant increase in the Young modulus of elasticity in the trypan blue-stained samples (10.5 ± 1.4 kPa) compared with the control (5.8 ± 0.8 kPa), (P < 0.0001).
  
  
  CONCLUSIONS
  Our results suggest that trypan blue may decrease DM elasticity and consequently increase its stiffness. This may influence the graft adherence when used for endothelial keratoplasty.
authors.affiliation: *Loyola University of Chicago, Maywood, IL; †Thomas John Vision Institute, Oak Lawn, IL; ‡Iladevi Cataract and IOL Research Centre, Ahmedabad, Gujarat, India; §Department of Chemical Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India; ¶Ocular Surface Center, Miami, FL; and ‖Department of Ophthalmology, Florida International University, Herbert Wertheim College of Medicine, Miami, Florida.
authors.forename: Thomas
authors.initials: T
authors.lastname: John
authors.forename: Alpesh
authors.initials: A
authors.lastname: Patel
authors.forename: Abhay
authors.initials: A
authors.lastname: Vasavada
authors.forename: Man
authors.initials: M
authors.lastname: Singh
authors.forename: Vandana
authors.initials: V
authors.lastname: Nath
authors.forename: Anny M S
authors.initials: AM
authors.lastname: Cheng
authors.forename: Hosam
authors.initials: H
authors.lastname: Sheha
mesh_terms: D000328:Adult; D000368:Aged; D004396:Coloring Agents / Q000494:pharmacology*; D003886:Descemet Membrane / Q000187:drug effects*; D055119:Elastic Modulus; D004548:Elasticity / Q000187:drug effects*; D054459:Elasticity Imaging Techniques; D005125:Eye Banks; D006801:Humans; D018625:Microscopy, Atomic Force; D008875:Middle Aged; D014019:Tissue Donors; D014343:Trypan Blue / Q000494:pharmacology*
chemical_list: D004396:Coloring Agents; D014343:Trypan Blue