@article {142,
	title = {In vivo assessment of corneal barrier function through non-invasive impedance measurements using a flexible probe},
	journal = {Journal of Physics: Conference Series},
	volume = {434},
	year = {2013},
	pages = {012072},
	abstract = {<p>The cornea is a transparent structure composed of three layers: the epithelium, the stroma and the endothelium. To maintain its ransparency the stroma remains in a constant state of dehydration. Consequently, any ion flow disorder through the covering layers can compromise the barrier function and, therefore the corneal homeostasis. Since ionic permeability has a fundamental impact on the passive electrical properties of living tissues, in this work it is proposed and demonstrated a diagnosis method based on tetrapolar impedance measurements performed by electrodes placed on the corneal surface. The contribution of each cornea layer to the total measured impedance has been analysed over a frequency range. Following the obtained guidelines, a flexible probe with integrated electrodes has been developed and manufactured using SU-8 photoresin. The feasibility of the proposed method has been evaluated in vivo by monitoring corneal epithelium wound healing. Obtained impedance measurements have been compared with measurements of permeability to sodium fluorescein from different excised corneas. Successful results demonstrate the feasibility of this novel flexible sensor and its capability to quantify corneal permeability in vivo in a noninvasive way.</p>
},
	url = {http://stacks.iop.org/1742-6596/434/i=1/a=012072},
	author = {A Guimera and X Illa and E Traver and S Marchan and C Herrero and C Lagunas and M J Maldonado and Antoni Ivorra and R Villa}
}
@article {Guimera2010,
	title = {{Non-invasive assessment of corneal endothelial permeability by means of electrical impedance measurements.}},
	journal = {Medical engineering \& physics},
	volume = {32},
	number = {10},
	year = {2010},
	pages = {1107{\textendash}15. {\textcopyright} 2010 IPEM. Published by Elsevier Ltd.},
	abstract = {<p>The permeability of the corneal endothelial layer has an important role in the correct function of the cornea. Since ionic permeability has a fundamental impact on the passive electrical properties of living tissues, here it is hypothesized that impedance methods can be employed for assessing the permeability of the endothelial layer in a minimally invasive fashion. Precisely, the main objective of the present study is to develop and to analyze a minimally invasive method for assessing the electrical properties of the corneal endothelium, as a possible diagnostic tool for the evaluation of patients with endothelial dysfunction. A bidimensional model consisting of the main corneal layers and a four-electrode impedance measurement setup placed on the epithelium has been implemented and analyzed by means of the finite elements method (FEM). In order to obtain a robust indicator of the permeability of the endothelium layer, the effect of the endothelium electrical properties on the measured impedance has been studied together with reasonable variations of the other model layers. Simulation results show that the impedance measurements by means of external electrodes are indeed sufficiently sensitive to the changes in the electrical properties of the endothelial layer. It is concluded that the method presented here can be employed as non-invasive method for assessing endothelial layer function.</p>
},
	keywords = {Biomedical Engineering, Biomedical Engineering: methods, Corneal, Corneal: abnormalities, Corneal: metabolism, Corneal: pathology, Electric Impedance, Electric Impedance: diagnostic use, Endothelium, Finite Element Analysis, Humans, Permeability, Reproducibility of Results, Sensitivity and Specificity},
	issn = {1873-4030},
	doi = {10.1016/j.medengphy.2010.07.016},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/20832346},
	author = {A Guimera and Antoni Ivorra and Gabriel, G and R Villa}
}
