title: Measurement of corneal endothelial impedance with non-invasive external electrodes--a theoretical study.
abstract: The corneal endothelial cell layer function is critical for the maintenance of hydration and transparency of the cornea. Recent advances in corneal lamellar transplantation point to the need for reliable, non-invasive and rapid endothelial function assessment. Findings using an invasive electrode in an experimental animal model have suggested an association between bioimpedance parameters and endothelial cell function. Currently, however there is no clinical device that allows for non-invasive measurements of endothelial layer electrical impedance. This report is a finite element simulation study that models the human eye. It evaluates the feasibility of using external non-invasive electrodes to detect changes in endothelial layer electrical properties as a function of electrode location and measurement frequencies. The findings show that the ratio between the potential recorded at low and high frequencies is sensitive to changes in endothelial resistivity as well as endothelial capacitance. Moreover, the optimal electrode configuration yielding the highest sensitivity is one where the current injecting electrodes are oppose to each other and the voltage recording electrodes are adjacent to the current injecting electrodes. This first-order theoretical study suggests that a non-invasive device which measures electrical properties of the endothelial layer from the exterior of the eye could be developed. Clearly further animal and human studies are required to develop a reliable clinical tool.
authors.affiliation: Center for Bioengineering in the Service of Humanity and Society, The Selim and Rachel Benin School of Computer Science and Engineering, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel. yossimandel@bezeqint.net
authors.forename: Yossi
authors.initials: Y
authors.lastname: Mandel
authors.forename: Shlomi
authors.initials: S
authors.lastname: Laufer
authors.forename: Boris
authors.initials: B
authors.lastname: Rubinsky
mesh_terms: D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D025802:Electric Capacitance; D017097:Electric Impedance; D004566:Electrodes; D004728:Endothelium, Corneal / Q000166:cytology*; D008962:Models, Theoretical