DEVICE FOR MONITORING INTRAOCULAR PRESSURE

• US 20130184554A1
• Filed: 10/20/2011
• Published: 07/18/2013
• Est. Priority Date: 10/20/2010
• Status: Active Grant

• Current Assignee: Contact Lens Precision Laboratories Limited (Seed Co., Ltd. /7743/), University of Dundee
• Original Assignee: Contact Lens Precision Laboratories Limited (Seed Co., Ltd. /7743/), University of Dundee
• Inventors: Elsheikh, Ahmed, Clamp, John
• Granted Patent: US 9,247,877 B2
• Time in Patent Office: Days
• US Class Current: 600/399
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers

Abstract

Disclosed is a device adapted to measure intraocular pressure comprising: a corneal contact lens having a pressure sensor mounted in a recess or cavity in the contact lens, and wherein the contact lens has a back surface which is formed so as to protrude in a desired portion beyond the profile of the adjacent part of the lens and thus to press against the cornea, which protruding portion experiences a reactive deformation which is detected directly or indirectly by the pressure sensor.

Claims

1. A device adapted to measure intraocular pressure comprising:

a corneal contact lens having a pressure sensor mounted in a recess or cavity in the contact lens, and wherein the contact lens has a back surface which is formed so as to protrude in a desired portion beyond the profile of the adjacent part of the lens and thus to press against the cornea, which protruding portion experiences a reactive deformation which is detected directly or indirectly by the pressure sensor.

2. A device according to claim 1, wherein the protruding portion experiences a reactive deformation when the eyelids are closed but not when the eyelids are open.

3. A device according to claim 1, wherein the protruding portion of the lens underlies the recess or cavity.

4. A device according to claim 1, wherein the recess or cavity is annular or arcuate.

5. A device according to claim 1, wherein the pressure sensor comprises a capacitor, the capacitance of which is altered by the reactive deformation experienced by the protruding portion of the contact lens.

6. A device according to claim 1, wherein there is provided a stiff “

bridge”

member accommodated within the recess or cavity, which “

bridge”

member has an elastic modulus which is greater than that of the contact lens material.

7. A device according to claim 6, wherein the pressure sensor comprises a capacitor, one of the plates of which is attached to the stiff bridge member.

8. A device according to claim 6, wherein the pressure sensor comprises a diaphragm which overlies the protruding portion of the lens, the diaphragm being formed of a material which has an elastic modulus which is intermediate between that of the contact lens material and that of the stiff bridge member.

9. A device according to claim 8, wherein the pressure sensor comprises a capacitor, one of the plates of which is attached to the diaphragm.

10. A device according to claim 1, wherein the protruding portion is joined to the rest of the contact lens by one or more weakened areas which are thinner than the main body of the lens.

11. A device according to claim 10, wherein there is provided a stiff “

bridge”

member accommodated within the recess or cavity, which “

bridge”

member has an elastic modulus which is greater than that of the contact lens material, and wherein the stiff “

bridge”

portion has legs or supports which act on the one or more weakened areas, such that pressure on the bridge from the eyelid is applied to the weakened areas, to push the protruding portion of the lens against the cornea.

12. A device according to claim 1, wherein the contact lens further comprises a coil of electrically conducting material.

13. A device according to claim 1, wherein the contact lens is adapted and configured such that the protruding portion and/or the pressure sensor, when in situ on an eye of a subject, overlies the transitional region of the cornea of the eye.

14. A device according to claim 13, wherein the protruding portion and/or the pressure sensor is located so as to overlie the transitional region of the cornea and not to extend therebeyond.

15. A device according to claim 1, comprising a central aperture formed in the contact lens.

16. A device according to claim 15, wherein the central aperture is essentially circular.

17. A device according to claim 15, wherein the aperture is of sufficient dimension to allow the tip of an applanation tonometer to contact the cornea.

18. Apparatus for measuring TOP in a subject comprising a device according to claim 1, in combination with spectacles or an eye mask having an exciter coil which induces an emf in a respondent coil located on or in the contact lens.

19. Apparatus according to claim 18, wherein the exciter coil is positioned on the rear surface of the lens of the spectacles, the spectacles preferably comprising one or two corrective lenses.

20. Apparatus according to claim 18, wherein the spectacles or eye mask comprises, as an integral component, a source of electrical power which drives the exciter coil.

21. Apparatus according to claim 18, wherein the exciter coil is operated with an alternating current, the frequency of which is cycled over a desired range.

22. Apparatus according to claim 18, wherein the apparatus can monitor and record IOP over a period of at least 24 hours, the apparatus further comprising:

a digital signal processing unit and a data storage unit.

23. Apparatus according to claim 22, further comprising one or more of the following:

a signal generator unit, a user interface, and a data communication unit for transferring data via a wire or wirelessly.

24. Apparatus according to claim 18, wherein all of the necessary components are provided, in combination, on the contact lens or the spectacles or eye mask.

25. Apparatus according to claim 22, adapted for measuring and/or monitoring OPA.

26. A method of determining the TOP or OPA in the eye of a subject, the method comprising the steps of:

(a) introducing onto the eye of the subject a device in accordance with claim 1;

(b) obtaining at least one measurement using the device; and

(c) using the at least one measurement from step (b) to determine the TOP or OPA of the subject'"'"'s eye.

27. A method according to claim 26, wherein step (b) comprises obtaining a plurality of measurements.

28. A method according to claim 27, wherein the plurality of measurements are obtained over a period of at least 12 hours.

29. A method according to claim 26, wherein the at least one measurement in a period in which the subject is asleep.

30. A method according to claim 26, further comprising the step of diagnosing the existence of glaucoma in the subject'"'"'s eye, based on the determined TOP or OPA.

31. A method of measuring or estimating corneal stiffness, the method comprising the steps of:

(a) introducing onto the eye of a subject a first device in accordance with claim 1, and obtaining a first data set relating to IOP in the subject'"'"'s eye;

(b) removing the first device and introducing onto the same eye a second device in accordance with claim 1, the second device differing in some relevant characteristic, in a known manner, from the first device, and obtaining a second data set relating to IOP in the subject'"'"'s eye; and

(c) comparing the first and second data sets to allow a measurement or estimation of the corneal stiffness of the subject'"'"'s eye.

32. A method according to claim 31 wherein the second device differs from the first device in the steepness of curvature of the protruding portion of the contact lens.

33. A method according to claim 31, wherein the first device has a protruding portion with a greater steepness of curvature than that of the first device, and where the first device is worn for less than 10 minutes and the second device is worn for 24 hours or more.

34. A method of directly calibrating a device in accordance with claim 17, the method comprising the steps of:

(a) introducing onto the eye of a subject the device in accordance with claim 17;

(b) obtaining at least one measurement using said device;

(c) using an applanation tonometer to obtain one or more readings of IOP or OPA in the subject'"'"'s eye whilst the device of the invention is in situ on the eye, by passing the tip of the applanation tonometer through the aperture, provided in the device, far enough to contact the cornea and obtain one or more readings of IOP or OPA; and

(d) directly calibrating the device of the invention using the measurement obtained in step (b) and the one or more readings of IOP or OPA obtained in step (c).

35. A method according to claim 34, wherein steps (b) and (c) are performed, in either order, within 3 minutes of each other.

36. A stiff bridge member for use in a device in accordance with claim 1, the bridge member being circular or arcuate.

37. A bridge member according to claim 36, further comprising any one or more of the following:

a respondent coil;

a first conducting element, acting as a first capacitor plate;

a diaphragm, having an elastic modulus intermediate in value between that of the bridge member and that of a soft contact lens with which the bridge member is to be associated; and

a second conducting element, acting as a second capacitor plate.

41. Apparatus according to claim 18, wherein the exciter coil is positioned on the rear surface of the lens of the spectacles, the spectacles comprising one or two corrective lenses.

42. A stiff bridge member for use in a device in accordance with claim 1, the bridge member being circular or arcuate having an elastic modulus in the range 300 MPa to 3 GPa.

43. A bridge member according to claim 36, further comprising any one or more of the following:

a respondent coil embedded in the bridge member;

a first conducting element, acting as a first capacitor plate;

a diaphragm, having an elastic modulus intermediate in value between that of the bridge member and that of a soft contact lens with which the bridge member is to be associated; and

a second conducting element, acting as a second capacitor plate located on the diaphragm.

38-40. -40. (canceled)