ELECTROLYTES IN THE CORNEA - A THERAPEUTIC CHALLENGE

Background: Reported here are the results of electrolyte measurements in different layers of 70 apparently normal human corneas. Methods: Sa mples were examined by energy-dispersive Xray analysis under calibrate d conditions in a scanning electron microscope. The method allows the simultaneous quantitative analysis of, among others, sodium (Na), chlo ride (Cl), phosphorus (P) and potassium (K). The results are related t o the dry weight of the analyzed samples. Four distinct layers, subepi thelium, middle stroma, posterior stroma and Descemet's membrane, were analysed in each cornea. Results: In the middle stroma we found conce ntrations of: sodium 0.609 +/- 0.13, chloride 0.557 +/- 0.115, potassi um 0.058 +/- 0.02 and phosphorus 0.038 +/- 0.01 (mmol/kg dry weight). Conclusion: The collation of normal electrolyte concentrations provide s reference values for future studies on changes of the corneal electr olyte composition in diseased or injured eyes. The electrolyte composi tion of rinsing fluids or eye drops should be adjusted to that of the corneal stroma. Phosphate buffer, for example, is not a good vehicle f or topical eye treatments and should be replaced by organic buffering systems.