METHOD AND DEVICE FOR MONITORING BIOMECHANICAL PROPERTIES OF THE EYE
First Claim
1. A method for monitoring biomechanical properties of the eye, using a measuring arrangement which comprises a measuring device designed to be born in the manner of a contact lens, the measuring device comprising a force detector in operative engagement with a protrusion directed towards the cornea of an eye once the measuring device is applied to the eye, the measuring device being flexible in order to be pressed against the cornea by a lid of the eye moving over the measuring device, wherein the method comprises the following steps:
- measuring and storing force values and indication of time when the force values occurred;
determining the time tstart when the force values start to be significantly greater than zero, time tstop at which the force values after tstart are no more substantially greater than zero, equivalent to the times when the protrusion first gets in contact with the cornea respectively disconnects therefrom;
determining a maximum force value between tstart and tstop in order to determine the phases of eye closing, eye being closed, and eye opening;
deriving from the force values and the corresponding time values between tstart and tEnd a value indicative of the tension of the cornea.
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Accused Products
Abstract
A contact lens shaped measuring device (1) includes sensor (3) having a protrusion (14) towards the cornea (22). The measuring device (1) is flexible to a degree that it is flattened by a closing eye lid and the protrusion creates an indentation of the cornea. The occurring force on the protrusion is measured by the sensor. Applying a constant lid acceleration/deceleration model to the movement of the lid and a mechanical model to the cornea, the tension of the cornea is determined and deduced from the force measured with the lid closed, yielding the true intraocular pressure. In an alternative, the protrusion is characterized by a discontinuity in its shape, or the sensor is subdivided, each subsensor being characterized by a protrusion of different shape. With the values obtained as extrema and at the discontinuity or with different protrusions, the cornea tension can be obtained by a (linear) extrapolation.
10 Citations
13 Claims
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1. A method for monitoring biomechanical properties of the eye, using a measuring arrangement which comprises a measuring device designed to be born in the manner of a contact lens, the measuring device comprising a force detector in operative engagement with a protrusion directed towards the cornea of an eye once the measuring device is applied to the eye, the measuring device being flexible in order to be pressed against the cornea by a lid of the eye moving over the measuring device, wherein the method comprises the following steps:
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measuring and storing force values and indication of time when the force values occurred; determining the time tstart when the force values start to be significantly greater than zero, time tstop at which the force values after tstart are no more substantially greater than zero, equivalent to the times when the protrusion first gets in contact with the cornea respectively disconnects therefrom; determining a maximum force value between tstart and tstop in order to determine the phases of eye closing, eye being closed, and eye opening; deriving from the force values and the corresponding time values between tstart and tEnd a value indicative of the tension of the cornea. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for measuring properties of the eye substantially shaped as a contact lens, wherein the device comprises a sensor of annular shape and peripherally arranged and having at least one protrusion directed towards the eye when applied to an eye, the device having such an overall flexibility that a lid closing over the device can deform it sufficiently to indent the cornea by the protrusion,
wherein the protrusion has at least two portions of different height.
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12. A device for measuring properties of the eye substantially shaped as a contact lens, wherein the device comprises a sensor of annular shape and peripherally arranged and having a protrusion directed towards an eye when applied to the eye, the device having such an overall flexibility that a lid closing over the device can deform it sufficiently to indent the cornea by the protrusion,
wherein the protrusion has flanks which comprises at least one step creating a transition zone from a larger protrusion to a smaller protrusion.
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13. A device for measuring properties of the eye substantially shaped as a contact lens, wherein the device comprises a sensor of annular shape and peripherally arranged and having a protrusion directed towards an eye when applied to the eye, the device having such an overall flexibility that a lid closing over the device can deform it sufficiently to indent the cornea by the protrusion,
wherein the sensor is subdivided in at least to subsensors, the subsensor having protrusions of different size, so that the subsensors timely shifted touch the cornea when the lid closes over the device.
Specification