Intraocular pressure measurement

• US 6,440,070 B2
• Filed: 05/07/2001
• Issued: 08/27/2002
• Est. Priority Date: 05/08/2000
• Status: Expired due to Fees

• Current Assignee: Ness-Tec Ophthalmic Systems, Ltd.
• Original Assignee: Ness-Tec Ophthalmic Systems, Ltd.
• Inventors: Israel, Henry
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US09/849,407
• Publication Number:
  US 20020010393A1
• Time in Patent Office: 477 Days
• Field of Search: 600/398, 600/401, 600/405, 600/558
• US Class Current: 600/398
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers
• CPC Class Codes: A61B 8/10 Eye inspection

Abstract

Apparatus for measuring intra-ocular pressure of an eye includes a housing and a processor. The housing has a protuberance with a flat surface and the processor includes a distance-measuring unit and a force-measuring unit. Intra-ocular pressure is calculated based on force/distance relationships, where the distance includes a measurement to an internal element of the eye. The processor calculates intra-ocular pressure by determining a zero displacement pressure.

Claims

1. Apparatus for measurement of intra-ocular pressure of an eye, the apparatus comprising:

a distance-measuring unit for measuring a distance from an external surface of said eye to an internal element of said eye; and

a processor for generating said intra-ocular pressure from at least said distance measurement.

2. The apparatus of claim 1 wherein said distance-measuring unit is an ultrasound transducer.

3. The apparatus of claim 1 wherein said distance-measuring unit is a laser.

4. The apparatus of claim 1 wherein said external surface is selected from the group consisting of an eyelid and a cornea.

5. The apparatus of claim 1 wherein said internal element is selected from the group consisting of a lens and a retina.

6. The apparatus of claim 1 wherein said processor is configured to generate said intra-ocular pressure by calculation of a zero displacement value.

7. The apparatus of claim 1 wherein said processor comprises a force measuring unit, and wherein said intra-ocular pressure is generated from said distance measurement and a force measurement.

8. A non-invasive ocular pressure measuring unit comprising:

a housing having a protuberance with a generally flat surface; and

a processor comprising at least a force-measuring unit, for measuring a force applied by said protuberance to an eyelid.

9. The unit of claim 8, wherein said processor further comprises a distance measuring unit, for measuring a distance from said eyelid to an internal element of an eye.

10. The unit of claim 9 wherein said distance-measuring unit is selected from the group consisting of an ultrasound transducer and a laser.

11. The unit of claim 8 wherein said force-measuring unit is a load cell.

12. A method for detecting intra-ocular pressure of an eye, the method comprising the steps of:

measuring a distance from an external surface of an eye to an internal element of an eye; and

calculating said intra-ocular pressure from said distance.

13. The method of claim 12, wherein said external surface is selected from the group consisting of an eyelid and a cornea.

14. The method of claim 12 wherein said internal element is selected from the group consisting of a lens and a retina.

15. A method for detecting intra-ocular pressure of an eye, the method comprising the steps of:

having an apparatus placed against an eyelid, wherein said apparatus comprises at least a force-measuring unit;

measuring at least a force resulting from said placement; and

calculating an intra-ocular pressure from said at least force measurement.

16. The method of claim 15, wherein said step of measuring at least a force further comprises measuring a distance from said eyelid to an internal element of said eye, and wherein said step of calculating comprises calculating an intra-ocular pressure from said distance measurement.

17. The method of claim 16, wherein said step of calculating comprises the steps of:

determining a function for pressure relating said force measurements to said distance measurements; and

calculating a value for intra-ocular pressure based on said function at zero displacement.

18. A method for correcting for material properties of an external element of an eye, the method comprising the steps of:

measuring a force applied to said external element;

measuring a distance from said external element to an internal element of said eye; and

generating a zero displacement value from a function relating said force and said distance.

19.The method of claim 18 wherein said external element is selected from the group consisting of an eyelid and a cornea.

20.The method of claim 18, wherein said internal element is selected from the group consisting of a lens and a retina.

19. The method of claim 18 wherein said function comprises a linear segment.

20. The method of claim 18 wherein said value is a pressure value.

21. The method of claim 18, wherein said material properties are selected from the group consisting of compressibility, thickness and elasticity.

22. A system for measurement of intra-ocular pressure of an eye, the system comprising:

a housing having a protuberance with a generally flat surface; and

a processor, said processor comprising;

a force measuring unit for measuring a force applied by said protuberance to an external surface of said eye; and

a distance measuring unit for measuring a distance from said external surface of said eye to an internal element of said eye,

wherein said processor is configured to calculate a relationship between said force and distance measurements so as to produce a definable function of pressure over a range of values.

24. The system of claim 24, wherein said internal element is selected from the group consisting of a lens and a retina.

23. The system of claim 24, wherein said external surface is selected from the group consisting of an eyelid and a cornea.

25. The system of claim 24, wherein said definable function includes a linear portion.

26. The system of claim 24 wherein said distance measuring unit is selected from the group consisting of an ultrasound transducer and a laser.

27. The system of claim 24 wherein said force measuring unit is a load cell.