Noncontacting portable infrared intra-ocular pressure sensor

• US 5,813,982 A
• Filed: 02/22/1994
• Issued: 09/29/1998
• Est. Priority Date: 02/22/1994
• Status: Expired due to Fees

• Current Assignee: Francis I. Baratta
• Original Assignee: Francis I. Baratta
• Inventors: Baratta, Francis I.
• Primary Examiner(s): Lacyk, John P.
• Application Number:
  US08/199,636
• Time in Patent Office: 1,680 Days
• Field of Search: 128/645-52, 128/897-98, 128/736, 128/664, 364/557, 374/100, 374/120, 374/121, 374/129, 374/130, 374/131, 600/398-406, 600/549, 600/473-477
• US Class Current: 600/398
• CPC Class Codes: A61B 3/165 Non-contacting tonometers
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/049 Casings for tympanic thermometers
• CPC Class Codes: G01J 5/05 Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
• CPC Class Codes: G01J 5/064 Ambient temperature sensor; Housing temperature sensor; Constructional details thereof
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables

Abstract

Medical studies have shown that when the pressure within the eye rises above normal the flow of blood is suppressed to the veins and the optic nerve fibers causing a reduction of temperature at those locations. If such conditions are allowed to exist over a period of time the subject is in danger of experiencing loss of peripheral vision, called glaucoma.

This invention presents an improved way to determine indirectly intra-ocular pressure of the human eye through the use of a noncontacting, nonirrating, infrared temperature sensing device. This is accomplished by accurately measuring the temperature at the macula and fovea sites located at the back of the eye and the core body temperature as the individual'"'"'s base temperature using the same tympanic temperature measuring device. The difference in these temperatures, calibrated in terms of intra-ocular pressure, reveals the potential danger of impending glaucoma. The read-out can easily be put in terms of a threshold warning to the user as a visual and/or audible warning signal. The device can be employed as an accurate tonometer to replace the presently used mechanical tonometers, or as a screening test.

Claims

1. A method to detect relative inter-ocular pressure where:

a first sensor is directed at the tympanic membrane within one ear of a patient, and where said first sensor generates a first signal proportional to a core temperature of said patient; and

where a first signal processing means converts said first signal into a core output signal, and where a second detector is directed at the macula of one eye of said patient by a directing means; and

where said second sensor generates a second signal proportional to the temperature of said patient'"'"'s macula, and where a second signal processing means converts said second signal into a macula output signal, and where said core output signal and said macula output signal are compared by a primary comparing means, and where an output from said means is further compared with a preset value by a secondary comparison means, and where when the output exceeds preset values an alarm processing means provides audible, visible, tactile, electronic, or printed warning indicators.

9. The claim of 1 where said dual sensors are infrared sensors.

10. The claim of 9 where said infrared sensors are directed for said first sensor at the tympanic membrane and for said second sensor at the macula of the eye.

2. The method in 1 where a further focusing apparatus is inserted in the optical path between the eye and the second sensor, and where an adjustable or fixed focal distance is maintained by a housing holding said focusing apparatus and said second sensor.

3. The method in 2 where said focusing apparatus is a Fresnel lens.

4. The method in 1 where a single sensor is used in place of said first and second sensor, said single rotatable sensor mounted by rotatable mounting means to sense tympanic and macular temperature in series.

5. The method in 4 where said rotatable means is a two position holder said single sensor.

6. The method in 4 where said rotatable mounting means is attached to the unit which houses ophthalmoscopic instruments and which guides, and enables focusing of said single sensor.

7. The method in 1 where a further analog or digital reading of comparative temperatures is provided.

8. The method in 1 where a further processing comparator means follows said comparison means and said processing comparator means compares said signed proportional signal to an oppositely signed reference signal, and where if said signal has a signed magnitude signal indicating said reference signal is larger (smaller) than said signed proportional signal, then said signed magnitude signal is directed to said output processing means.

11. The method in 4 where said single sensor is an infrared sensor.

12. The method in 11 where said infrared sensor is directed at the tympanic membrane and for said sensor at the macula of the eye.

13. A process to identify high intra-ocular pressure where, dual sensors are provided, the first sensor directed at an area of the body by first directing means, which can produce a first signal directly related to a body core temperature, and a second sensor directed through the pupil of an eye by a second directed means to produce a second output signal directly relatable to the macula temperature of the eye, and where a comparison means input results of said first signal and said second signal output signal and produces a signed signal proportional to the difference magnitude between said first signal and said second signed output signal, and where said signal proportional signal is processed by output processing means by display means to produce a readout which is relatable to intra-ocular pressure.

14. The process in 13 where said directed means is a focusing lens within a housing which is adjustable while touching at least one reference point on the head.

15. The process in 14 where said focusing means is a Fresnel lens.

16. The process in 14 where said focusing means is incorporated within the unit that also contains ophthalmoscopic instruments and which includes reference scales and focusing means.

17. The process in 13 where a single sensor is employed which is serially locatable for measuring both tympanic temperature and macular temperature.

18. The process in 17 where a storage device stores the temperature information from said tympanic and said macular temperature prior to said comparison means and which provides input to said comparison means.

19. A device lo measure macular temperature and compare it to the tympanic temperature where a sensor detects the tympanic temperature and this temperature value is electronically or manually inputted to a comparison means which takes a signal from an infrared sensor viewing the temperature of the macula of the eye through a focused lens, and where said comparison means provides a differential output indicating the signed variance between the tympanic and macular temperatures.

20. The device in 19 where said focused lens is a Fresnel lens.