title: In vivo oxygen uptake into the human cornea.
abstract: OBJECTIVE
  We provide a new procedure to quantify in situ corneal oxygen uptake using the micropolarographic Clark electrode.
  
  
  METHODS
  Traditionally, upon placing a membrane-covered Clark microelectrode onto a human cornea, the resulting polarographic signal is interpreted as the oxygen partial pressure at the anterior corneal surface. However, the Clark electrode operates at a limiting current. Hence, oxygen flux is directly detected rather than partial pressure. We corrected this misunderstanding and devised a new analysis to quantify oxygen uptake into the cornea. The proposed analysis is applied to new polarographic data for 10 human subjects during open-eye oxygen uptake.
  
  
  RESULTS
  Average open-eye corneal oxygen uptake over 10 subjects is approximately 11 μL/(cm(2) h), approximately five times larger than the average reported by researchers who invoke the original mathematical analysis. Application of the classical interpretation scheme to our experimental data also garners uptake values that are approximately a factor of three to five times smaller than those obtained with our new procedure.
  
  
  CONCLUSIONS
  The classical procedure originally developed by Fatt and colleagues misinterprets the behavior of the Clark microelectrode. We corrected the analysis of the in situ polarographic technique to provide a simple yet rigorous procedure for analyzing both previous data in the literature and those newly obtained. Our proposed interpretation scheme thus provides a reliable tool for in vivo assessment of corneal oxygen uptake.
authors: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462, USA.
authors: Sho C
authors: SC
authors: Takatori
authors: Percy Lazon
authors: PL
authors: de la Jara
authors: Brien
authors: B
authors: Holden
authors: Klaus
authors: K
authors: Ehrmann
authors: Arthur
authors: A
authors: Ho
authors: Clayton J
authors: CJ
authors: Radke
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D003315:Cornea / Q000378:metabolism*; D004058:Diffusion; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D008839:Microelectrodes; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010313:Partial Pressure; D011048:Polarography / Q000295:instrumentation / Q000379:methods*
chemical_list: D010100:Oxygen