Methods for assessing a physiological state of a mammalian retina

• US 20050159662A1
• Filed: 08/26/2004
• Published: 07/21/2005
• Est. Priority Date: 01/21/2004
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Seibel, Eric J., Palczewski, Krzysztof, Imanishi, Yoshikazu, Sires, Bryan S.
• Granted Patent: US 7,706,863 B2
• Time in Patent Office: Days
• US Class Current: 600/473
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 3/1025 for confocal scanning
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence

Abstract

In one aspect the present invention provides methods for assessing a physiological state of a mammalian retina in vivo, the methods of this aspect of the invention each include the steps of: (a) irradiating a portion of a mammalian retina, in vivo, with light having a wavelength in the range of from 600 nm to 1000 nm at an intensity sufficient to stimulate two-photon-induced fluorescence in the retina; and (b) assessing a physiological state of the retina by analyzing the fluorescence.

Claims

1. A method for assessing a physiological state of a mammalian retina in vivo, the method comprising the steps of:

(a) irradiating a portion of a mammalian retina, in vivo, with light having a wavelength in the range of from 600 nm to 1000 nm at an intensity sufficient to stimulate two-photon-induced fluorescence in the retina; and

(b) assessing a physiological state of the retina by analyzing the two-photon-induced fluorescence.

2. The method of claim 1 wherein the retina is a human retina.

3. The method of claim 1 wherein the retina is a canine retina or a feline retina.

4. The method of claim 1 wherein the retina is irradiated using a laser.

5. The method of claim 1 wherein the light used to irradiate the retina has a wavelength in the range of from 650 nm to 850 nm.

6. The method of claim 1 wherein the light used to irradiate the retina has a wavelength in the range of from 710 nm to 740 nm.

7. The method of claim 1 wherein the light used to irradiate the retina irradiates a fixed focal volume of the retina and the light at the fixed focal volume has an optical power of from 0.05 mW to 25 mW.

8. The method of claim 1 wherein the light used to irradiate the retina irradiates a fixed focal volume of the retina and the light at the fixed focal volume has an optical power of from 0.5 mW to 15 mW.

9. The method of claim 1 wherein the two-photon-induced fluorescence has a wavelength in the range of from 400 nm to 640 nm.

10. The method of claim 1 wherein the irradiated portion of the mammalian retina has an area of from 250 μ

m² to 500,000 μ

m².

11. The method of claim 1 wherein a sclera, comprising an equatorial region, is located on one side of the retina, and the retina is irradiated through the sclera.

12. The method of claim 11 wherein two-photon-induced fluorescence that is emitted by the retina, and passes through the sclera, is analyzed to determine the physiological state of the retina.

13. The method of claim 11 wherein a clearing agent is applied to the sclera. before or during irradiation of the retina, to reduce the scattering of light passing through the sclera.

14. The method of claim 13 wherein the clearing agent is selected from the group consisting of glucose, glycerol, propylene glycol and dimethyl sulfoxide.

15. The method of claim 11 wherein the light that irradiates the retina travels through a portion of the sclera that is compressed, during irradiation of the retina, to reduce the scattering of light passing through the sclera.

16. The method of claim 11 wherein the retina is irradiated through the sclera and the two-photon-induced fluorescence is measured through the pupil.

17. The method of claim 11 wherein the retina is irradiated through a portion of the equatorial region of the sclera.

18. The method of claim 1 wherein the retina is irradiated through the pupil.

19. The method of claim 18 wherein the two-photon-induced fluorescence is measured through the pupil.

20. The method of claim 18 wherein the pupil is dilated.

21. The method of claim 1 wherein the portion of the mammalian retina is irradiated using a scanning laser ophthalmoscope.

22. The method of claim 1 wherein a sclera is located on one side of the retina, and second harmonically generated light emitted by the sclera is detected, and the detected light is used to determine whether the irradiating light, having a wavelength in the range of from 600 nm to 1000 nm, is focussed on the portion of the retina or on a portion of the sclera.

23. The method of claim 4 wherein the laser irradiates the portion of the retina with a repetition frequency in the range of from 76 MHz to 100 MHz.

24. The method of claim 4 wherein the laser irradiates the portion of the retina with light having a pulse length in the range of from 10 fs to 1000 fs.

25. The method of claim 1 wherein the physiological state of the retina is determined by visualizing retinosomes located within the retina.

26. The method of claim 1 wherein the physiological state of the retina is determined by measuring the total amount of two-photon-induced fluorescence emitted by a portion of the retina.

27. The method of claim 1 wherein retinosome fluorescence within the retina, increases after the retina is exposed to light, comprising light energy having a wavelength in the range of from 600 nm to 1000 nm, and the physiological state of the retina is assessed by measuring the increase in the retinosome fluorescence after the retina is exposed to the light.

28. The method of claim 1 wherein retinosome fluorescence within the retina increases then decreases after the retina is exposed to light, comprising light energy having a wavelength in the range of from 600 nm to 1000 nm, and the physiological state of the retina is assessed by measuring the increase and decrease in the retinosome fluorescence after the retina is exposed to the light.

29. The method of claim 1 wherein retinosome fluorescence within the retina increases then decreases after the retina is exposed to light, comprising light energy having a wavelength in the range of from 600 mn to 1000 nm, and the physiological state of the retina is assessed by measuring the decrease in the retinosome fluorescence.