title: Electrolytes in the cornea: a therapeutic challenge.
abstract: BACKGROUND
  Reported here are the results of electrolyte measurements in different layers of 70 apparently normal human corneas.
  
  
  METHODS
  Samples were examined by energy-dispersive X-ray analysis under calibrated conditions in a scanning electron microscope. The method allows the simultaneous quantitative analysis of, among others, sodium (Na), chloride (Cl), phosphorus (P) and potassium (K). The results are related to the dry weight of the analyzed samples. Four distinct layers, subepithelium, middle stroma, posterior stroma and Descemet's membrane, were analysed in each cornea.
  
  
  RESULTS
  In the middle stroma we found concentrations of: sodium 0.609 +/- 0.13, chloride 0.557 +/- 0.115, potassium 0.058 +/- 0.02 and phosphorus 0.038 +/- 0.01 (mol/kg dry weight) [corrected].
  
  
  CONCLUSIONS
  The collation of normal electrolyte concentrations provides reference values for future studies on changes of the corneal electrolyte composition in diseased or injured eyes. The electrolyte composition of rinsing fluids or eye drops should be adjusted to that of the corneal stroma. Phosphate buffer, for example, is not a good vehicle for topical eye treatments and should be replaced by organic buffering systems.
authors.affiliation: Department of Ophthalmology, RWTH Aachen, Germany.
authors.forename: N F
authors.initials: NF
authors.lastname: Schrage
authors.forename: S
authors.initials: S
authors.lastname: Flick
authors.forename: C
authors.initials: C
authors.lastname: Redbrake
authors.forename: M
authors.initials: M
authors.lastname: Reim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000838:Anions / Q000032:analysis*; D002412:Cations / Q000032:analysis*; D003315:Cornea / Q000737:chemistry* / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005128:Eye Diseases / Q000188:drug therapy; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000737:chemistry / Q000627:therapeutic use; D012016:Reference Values
chemical_list: D000838:Anions; D002412:Cations; D009883:Ophthalmic Solutions