Reflective non-contact ocular pulse analyzer for clinical diagnosis of eye and cerebrovascular disease

• US 8,740,795 B2
• Filed: 03/21/2008
• Issued: 06/03/2014
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Nuseon, LLC
• Original Assignee: Robert W. Allison Jr
• Inventors: Norris, John Lawrence, Allison, Robert W Jr.
• Primary Examiner(s): Hindenburg, Max
• Assistant Examiner(s): EISEMAN, ADAM JARED
• Application Number:
  US12/077,778
• Publication Number:
  US 20080242965A1
• Time in Patent Office: 2,265 Days
• Field of Search: 600/398, 600/399, 600/400, 600/401, 600/402, 600/403, 600/404, 600/405, 600/406
• US Class Current: 600/399
• CPC Class Codes: A61B 3/16 for measuring intraocular pressure, e.g. tonometers
• CPC Class Codes: A61B 3/165 Non-contacting tonometers

Abstract

An instrument has been designed to study the pulsatile motion of the eye by analysis of a beam of light reflected from the corneal surface. A laser light beam probe of small spot size and low divergence strikes the cornea apex and the reflected movement is recorded by a sensor. Analysis of the beam movement reveals the energy in the eye pulse without the necessity of physically touching the eye. The value of the intraocular pressure is determined from the calculated power spectrum. The sensitivity, accuracy and efficiency of the light beam makes possible studying both eyes concurrently and comparison of the pulse parameters of onset, amplitude and duration reveals any delay in circulation to an eye.

Claims

1. A method for evaluating eye disease by measuring eye surface movement during an ocular pulse, said method comprising:

identifying a blood pulse by sphygmomanometer on an arm, electrocardiography or ultrasonography;

using a laser light source to form a coherent gaussian, sub-millimeter diameter, low divergence probe beam that strikes the central cornea of the eye at a high angle of incidence;

using a processor synchronizing the beam with a blood pulse selected with a sphygmometer, electrocardiogram or ultrasonogram and record eye front surface movement;

magnifying a received reflection from the cornea of the beam that strikes a CCD camera sensor array;

calculating with a processor from the received beam reflected a plurality of parameters, including at least two from the group consisting of an ocular pulse amplitude waveform, a power spectra, a zero frequency amplitude of power spectrum, and non-zero frequency amplitudes, wherein the zero frequency amplitude of the power spectrum is a measure of energy in a mean intraocular pressure, and non-zero amplitudes are a measure of pressure changes during the ocular pulse that are indicative of eye disease.

2. The method of claim 1 using the heart pulse identified by arm sphygmomanometer, electrocardiogram or ultrasonography, wherein said forming includes striking the cornea of the eye.

3. The method of claim 1 using the heart pulse found by arm sphygmometer, electrocardiogram or ultrasonography, wherein the high angle of incidence is in the range of 65 to 75 degrees with respect to the visual axis.

4. The method of claim 3, wherein the high angle of incidence is 65 degrees.

5. The method of claim 3, wherein the high angle of incidence is 70 degrees.

6. The method of claim 3, wherein the high angle of incidence is 75 degrees.

7. The method of claim 1, wherein the sub-millimeter diameter is a beam diameter less than 500 micrometers.

8. The method of claim 1, wherein the low divergence probe beam has a divergence of approximately 1 mrad.

9. The method of claim 1, wherein the power of the probe beam is approximately 1 microwatt.

10. The method of claim 1, further comprising monitoring a blood pressure sensor correspondent to the eye.

11. The method of claim 1, where the spectral energy of higher frequency components of the eye are used to determine the cerebrovascular behavior of the eye and the mean pressure of the eye.

12. The method of claim 1, further comprising a forming and synchronizing a second probe beam to test a second eye concurrently.

13. The method of claim 12, further comprising magnifying a received reflection of the second beam and calculating in a processor a plurality of output parameters for said second beam.

14. The method of claim 13, wherein said processor calculated output parameters for said second beam are compared to the beam parameters to provide indicia of artery ailments.

15. The method of claim 14, wherein said artery ailments include at least one of the carotid artery and a chest artery.

16. The method of claim 1, wherein said processor generated output parameters provide indicia of at least one of glaucoma and ocular artery occlusion.