Eye tonometry apparatus, systems and methods

• US 20110054291A1
• Filed: 08/27/2010
• Published: 03/03/2011
• Est. Priority Date: 08/31/2009
• Status: Active Grant

• Current Assignee: Eniko Todorov Enikov, Gholam A. Peyman
• Original Assignee: Eniko Todorov Enikov, Gholam A. Peyman
• Inventors: Enikov, Eniko Todorov, Peyman, Gholam
• Granted Patent: US 7,959,570 B2
• Time in Patent Office: Days
• US Class Current: 600/405
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers

Abstract

A system for measuring intraocular pressure (IOP) of an eye, comprising a plurality of force sensors that are adapted to contact a surface of an eye, means for measuring the forces exerted on the force sensors when in contact with the eye surface, and processing means that is adapted to receive the measured forces and determine IOP of the eye as a function of the measured forces.

Claims

1. A system for measuring intraocular pressure (IOP) of an eye, comprising:

a plurality of force sensors, said force sensors being adapted to contact a surface of an eye;

means for measuring the forces exerted on said force sensors when said force sensors are in contact with said eye surface; and

processing means for processing said measured forces, said processing means being adapted to receive said measured forces and programmed to determine intraocular pressure (IOP) of the eye as a function of said measured forces.

2. The system of claim 1, wherein said IOP of the eye is determined by linear interpolation between two nearest force calibration curves representing first and second IOP values by the following relationship

p=(p_a*a+p_b*b)/(a+b)

where:

p_a and p_b represent said first and second IOP values, and

a and b represent vertical distances to said calibration curves reflecting said p_a and p_b.

3. The system of claim 1, wherein processing means is further adapted to determine outflow of aqueous humor from the eye as a function of said measured forces and measured changes in IOP over time.

4. The system of claim 3, wherein the following pressure-volume relationship is employed by said processing means to determine said outflow of aqueous humor

5. The system of claim 1, wherein said system includes force sensor alignment means for aligning said force sensors.

6. The system of claim 1, wherein said system includes force sensor linear transmission means that is adapted to extend and retract each of said force sensors.

7. The system of claim 6, wherein said force sensor linear transmission means is further adapted to secure said force sensors in extended and retracted positions.

12. The method of claim 1, including the step of subjecting said first and second force sensors to a first palpation sequence, said first palpation sequence comprising preprogrammed extension and retraction of said first and second force sensors.

8. A method for determining intraocular pressure (IOP) of an eye, comprising the steps of:

providing a palpation system having first and second force sensors, said first force sensor being in a first extended position and said second force sensor being in a first retracted position with respect to said first force sensor, said first and second force sensors being adapted to contact a surface of an eye, means for measuring forces exerted on said first and second force sensors when in contact with said eye surface, and processing means adapted to process said measured forces;

placing said palpation system on said surface of the eye, whereby said extended first force sensor is in contact with said eye surface;

applying a gradual first force to said eye surface with said palpation system and measuring force exerted on said first force sensor until said retracted second force sensor contacts said eye surface, whereby said second force sensor measures a first non-zero force; and

determining IOP of said eye as a function of said force exerted on said first force sensor when said second force sensor contacts said eye surface.

9. The method of claim 8, wherein said IOP of the eye is determined by linear interpolation between two nearest force calibration curves representing first and second IOP values by the following relationship

p=(p_a*a+p_b*b)/(a+b)

where:

p_a and p_b represent said first and second IOP values, and

a and b represent vertical distances to said calibration curves reflecting said p_a and p_b.

10. The method of claim 8, including the step of determining outflow of aqueous humor from the eye as a function of said measured forces and measured changes in IOP over time.

11. The method of claim 10, wherein the following pressure-volume relationship is employed to determine said outflow of aqueous humor

13. A method for determining intraocular pressure (IOP) of an eye, comprising the steps of:

providing a palpation system having first and second force sensors, means for measuring forces exerted on said first and second force sensors when in contact with an eye surface, and processing means adapted to process said measured forces;

placing said palpation system on a surface of the eye, whereby at least one of said first and second force sensors is in contact with said eye surface;

subjecting said first and second force sensors to a first palpation sequence, said first palpation sequence comprising preprogrammed extension and retraction of said first and second force sensors;

measuring a first plurality of forces exerted on said first force sensor and a second plurality of forces exerted on said second force sensor over a first period of time and at a plurality of IOP values during said palpation sequence;

generating a plurality of calibration curves from said measured first and second plurality of forces; and

determining IOP of the eye based on said generated plurality of calibration curves.

14. The method of claim 13, wherein said IOP is determined by generating a test curve and performing a linear interpolation between said test curve and two nearest calibration curves.

15. The method of claim 14, wherein the following relationship is employed to determine said IOP

p=(p_a*a+p_b*b)/(a+b).

16. A method for determining fluid displacement out of an eye, comprising the steps of:

providing a palpation system having first and second force sensors, means for measuring forces exerted on said first and second force sensors when in contact with an eye surface, and processing means adapted to process said measured forces;

placing said palpation system on a surface of the eye, whereby at least one of said first and second force sensors is in contact with said eye surface;

subjecting said first and second force sensors to a first palpation sequence, said first palpation sequence comprising preprogrammed extension and retraction of said first and second force sensors;

measuring a first plurality of forces exerted on said first force sensor and a second plurality of forces exerted on said second force sensor over a first period of time and at a plurality of IOP values during said palpation sequence;

generating a plurality of calibration curves from said measured first and second plurality of forces;

determining IOP of the eye based on said generated plurality of calibration curves;

and determining fluid displacement out of the eye as a function of the determined IOP.

17. The method of claim 16, wherein said IOP is determined by generating a test curve and performing a linear interpolation between said test curve and two nearest calibration curves.

18. The method of claim 17, wherein the following relationship is employed to determine said IOP

p=(p_a*a+p_b*b)/(a+b).

19. The method of claim 16, wherein said step of determining said fluid displacement of the eye includes determining time rate of change of fluid volume in the eye as a function of said IOP.