Systems and methods for non-invasive measurement of cassette pressure

• US 10,406,033 B2
• Filed: 08/31/2017
• Issued: 09/10/2019
• Est. Priority Date: 09/01/2016
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: Novartis Ag
• Inventors: Ekvall, Johan, Essex, Paul J., Todd, Kirk
• Primary Examiner(s): Ha, Nguyen Q.
• Application Number:
  US15/691,885
• Publication Number:
  US 20180055688A1
• Time in Patent Office: 740 Days
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61F 2009/00844 Feedback systems
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61M 1/73 comprising sensors or indicators for physical values
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2210/0612 Eyes
• CPC Class Codes: G01L 9/0077 for measuring reflected light

Abstract

A method and system provide a surgical system including a cassette, a console and an interferometric pressure sensing system coupled with the console. The cassette is for exchanging material with a patient and includes a wall and a reflector. The wall undergoes a deflection in response to a nonambient internal cassette pressure. The console is coupled with the cassette. The interferometric pressure sensing system is coupled with the console. The interferometric pressure sensing system includes a light source and a detector. The light source provides a first portion of light that is reflected off of the reflector and a second portion of light that bypasses the reflector. The first portion and the second portion of light are recombined to form an interference pattern. The deflection corresponds to a shift in the interference pattern detectable by the detector.

Claims

1. A surgical system comprising:

a cassette for exchanging material with a patient, the cassette including a wall and a reflector, the wall configured to undergo a deflection in response to a nonambient internal cassette pressure;

a console coupled with the cassette; and

an interferometric pressure sensing system coupled with the console, the interferometric pressure sensing system including a light source and a detector, the light source providing a first portion of light that is reflected off of the reflector and a second portion of light bypassing the reflector, the first portion and the second portion recombining to form an interference pattern, the deflection corresponding to a shift in the interference pattern detectable by the detector.

2. The surgical system of claim 1 wherein the interference pattern results from a difference in the physical paths of the first portion of the light and the second portion of the light.

3. The surgical system of claim 2 wherein the interferometric pressure sensing system includes a Michelson interferometer.

4. The surgical system of claim 3 wherein the Michelson interferometer includes a beam splitter and an additional reflector, the light from the light source passing through the beam splitter to form the first and second portions of the light, the additional reflector being coupled with a portion of the console.

5. The surgical system of claim 1, further comprising a processor configured to:

receive a signal from the detector related to the interference pattern;

based on the received signal, calculate the shift in the interference pattern; and

based on the calculated shift, determine a cassette pressure.

6. The surgical system of claim 1 wherein the light source and detector are integrated into the console.

7. The surgical system of claim 1 wherein the reflector is integrated into the wall of the cassette.

8. The surgical system of claim 1 wherein the reflector is coupled with the wall of the cassette.

9. The surgical system of claim 1 wherein the light source is a laser.

10. The surgical system of claim 1 wherein the light source has a wavelength and wherein the shift in the interference pattern corresponds to twice the deflection divided by the wavelength.

11. The surgical system of claim 1 wherein the nonambient pressure is greater than ambient pressure and the deflection is such that the reflector is closer to the detector.

12. The surgical system of claim 1 wherein the nonambient pressure is less than ambient pressure and the deflection is such that the reflector is further from the detector.

13. The surgical system of claim 1 wherein the interferometric pressure sensing system further includes a low pass filter coupled with the detector, the low pass filter for transmitting a signal that corresponds to the shift, the low pass filter having a pass band less than a threshold frequency.

14. The surgical system of claim 1 wherein the console includes a receptacle configured to receive the cassette.

15. An interferometric pressure sensing system for a surgical cassette, comprising:

a light source, configured to provide a light beam;

a beam splitter, configured to;

direct a first portion of the light beam towards a reflector on a wall of the surgical cassette, the wall configured to deflect in response to a nonambient internal cassette pressure; and

direct a second portion of the light beam to bypass the reflector en route to a detection unit;

the detection unit comprising a light beam sensor, a processor, and a memory, configured to;

receive a recombined light beam comprising the first portion reflected by the reflector and the second portion of the light beam which bypassed the reflector;

detect an interference pattern associated with the recombined light beam;

analyze the detected interference pattern to identify a shift in the interference pattern, the shift corresponding to a deflection of the wall of the surgical cassette; and

determine an internal cassette pressure based on the identified shift.

16. A method for treating an ophthalmic condition in an eye of a patient using a surgical system including a cassette and a console coupled with the cassette, the cassette including a wall, the method comprising:

providing light from a light source;

splitting the light into a first portion and a second portion, wherein;

the first portion is reflected off of a reflector on the wall of the cassette such that a first path of the first portion of the light includes the reflector, and

the second portion bypasses the reflector such that a second path of the second portion excludes the reflector;

recombining the first portion and the second portion to form an interference pattern, and

detecting a shift in the interference pattern, the shift in the interference pattern corresponding to a deflection in the wall of the cassette caused by a nonambient internal cassette pressure.

17. The method of claim 16, further comprising determining the deflection in the wall of the cassette based on the detected shift in the interference pattern.

18. The method of claim 16, further comprising determining the internal cassette pressure based on the detected shift in the interference pattern.

19. The method of claim 16, further comprising low-pass filtering a signal corresponding to the shift to provide a filtered signal having a frequency less than a threshold frequency.