Non-invasive sensor for determining functional characteristics of the cornea, device including said sensor and use thereof

A sensor for measuring impedance comprising n microelectrodes, wherein n is between 4 and 30, arranged on a substrate, the size and arrangement of the microelectrodes being suitable so that they contact a cornea simultaneously, and wherein the microelectrodes are selected for taking measurement in groups of 4 by way of 2 external microelectrodes and 2 internal microelectrodes, wherein the microelectrodes have an elongated shape, so as to have a length and a width, and are arranged in parallel according to their longest side, and wherein the width of an electrode assembly formed by the microelectrodes selected for taking the measurement is, or the distance between the middle lines of the external microelectrodes Ws is, 1 mm in the case of epithelium, 1.8 mm in the case of stroma or 5 mm in the case of endothelial layer.

A sensor for measuring impedance comprising n microelectrodes, wherein n is between 4 and 30, arranged on a substrate, the size and arrangement of the microelectrodes being suitable so that they contact a cornea simultaneously, and wherein the microelectrodes are selected for taking measurement in groups of 4 by way of 2 external microelectrodes and 2 internal microelectrodes, wherein the microelectrodes have an elongated shape, so as to have a length and a width, and are arranged in parallel according to their longest side, wherein the ratio of microelectrode gap Nre=Sei/Se, wherein Sei is the distance between the middle lines of the internal microelectrodes and Se is the distance between the middle lines of an internal microelectrode and the closest external microelectrode is 3.

A device for measuring impedance comprising:

• a sensor for measuring impedance comprising n microelectrodes, wherein n is between 4 and 30, arranged on a substrate, the size and arrangement of the microelectrodes being suitable so that they contact a cornea simultaneously, and wherein the microelectrodes are selected for taking measurement in groups of 4 by way of 2 external microelectrodes and 2 internal microelectrodes, wherein the microelectrodes have an elongated shape, so as to have a length and a width, and are arranged in parallel according to their longest side, and
• a multi-frequency impedance measuring equipment connected to the sensor.

A method for measuring impedance to determine the functional characteristics of the cornea comprising examining the cornea with a sensor comprising between 4 and 30 microelectrodes arranged on a substrate so as to contact the cornea simultaneously, and determining the functional characteristics of the cornea by taking measurement from the microelectrodes in groups of 4 of which 2 are external microelectrodes and 2 are internal microelectrodes, wherein each of the microelectrodes makes direct electrical contact with the cornea, wherein the width of an electrode assembly formed by the microelectrodes selected for taking the measurement Ws is less than 1.5 mm and the frequency at which the measurement is taken is less than 1 kHz in the case of epithelium, or wherein the width of the selected electrode assembly Ws is greater than 3 mm and the frequency at which the measurement is taken is comprised between 1 kHz and 100 kHz in the case of endothelium, or wherein the width of the selected electrode assembly Ws is comprised between 1.5 mm and 3 mm and the frequency at which the measurement is taken is greater than 100 kHz in the case of stroma.