Electro-optic binocular indirect ophthalmoscope

• US 6,350,031 B1
• Filed: 06/15/2000
• Issued: 02/26/2002
• Est. Priority Date: 07/29/1996
• Status: Expired due to Fees

• Current Assignee: Kameran Lashkari, Mark Harooni
• Original Assignee: Kameran Lashkari, Mark Harooni
• Inventors: Lashkari, Kameran, Harooni, Mark
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US09/595,554
• Time in Patent Office: 621 Days
• Field of Search: 351/205, 351/206, 351/200, 351/209, 351/210, 351/211, 351/212, 351/221, 351/246
• US Class Current: 351/221
• CPC Class Codes: A61B 3/1241 specially adapted for observation of ocular blood flow, e.g. by fluorescein angiography

Abstract

The present invention relates to a binocular indirect ophthalmoscope for observing and examining the fundus of the human eye. The ophthalmoscope of the invention integrates an electro-optic imaging system in the viewing optics of the ophthalmoscope. Advantageously, such integration permits the stereoscopic observation of the retina and choroid by employing radiation ranging from the near ultraviolet to the infrared, including the visible spectrum. A light source illuminates a desired portion of a patient'"'"'s fundus and the radiation reflected in response to the illuminating radiation is brought to focus to produce an aerial image of the fundus. A pair of ophthalmoscope lenses then magnify and image the aerial image along two different optical paths onto imaging sensors, such as charge coupled devices (CCDs) and image cameras, or image tubes such as image intensifiers. Visible displays, such as liquid crystal displays (LCDs), cathode ray tubes (CRTs), or the fluorescent screen of the image tube, then photoelectrically convert the fundus images formed on the imaging sensors and direct corresponding visible images thereof to an observer'"'"'s pupils by means of ocular lenses.

Claims

1. An ophthalmoscope comprising:

a light source for illuminating the interior of a patient'"'"'s eye with radiation, and

imaging devices for electro-optically imaging and displaying images of the interior of the patient'"'"'s eye to an observer, said images being formed from radiation reflected from the interior of the patient'"'"'s eye in response to said illuminating radiation and directed along two different optical paths.

2. The ophthalmoscope of claim 1, further including an optical fiber coupled to said light source for directing light to the interior of the patient'"'"'s eye.

3. The ophthalmoscope of claim 1, further comprising a viewing assembly for receiving the radiation reflected from the interior of the patient'"'"'s eye and for directing a portion of said reflected radiation along said two different optical paths to said imaging devices.

4. The ophthalmoscope of claim 3, further including a first filter disposed between said light source and the patient'"'"'s eye and a second filter disposed between the patient'"'"'s eye and the viewing assembly, wherein said first filter transmits radiation having a wavelength suitable for excitation of a fluorescent dye applied to the patient'"'"'s eye and said second filter transmits radiation having a wavelength corresponding to the fluorescence wavelength of said dye.

5. The ophthalmoscope of claim 1, further comprising a fixation target having a selected image thereon disposed between said illuminating means and the patient'"'"'s eye, thereby projecting said image onto the patient'"'"'s retina.

6. The ophthalmoscope of claim 5, wherein said fixation target comprises an image former.

7. The ophthalmoscope of claim 1, further comprising a filter for selectively filtering a predetermined spectrum of the radiation from said light source.

8. The ophthalmoscope of claim 1, further comprising a fixation target having a selected image thereon disposed between said light source and the patient'"'"'s eye, thereby projecting said image onto the patient'"'"'s retina.

9. The ophthalmoscope of claim 8, wherein said dye is excited by radiation in the near infrared region of the electromagnetic spectrum.

10. The ophthalmoscope of claim 9, wherein said dye comprises a fluorescein dye excitable by radiation having a wavelength in the blue portion of the spectrum, said dye fluorescing in the green portion of the spectrum upon excitation.

11. The ophthalmoscope of claim 1, further including a filter assembly comprising a plurality of filters disposed between said light source and the patient'"'"'s eye to generate the image of a portion of the patient'"'"'s retina at a plurality of wavelengths corresponding to transmission wavelengths of said filters.

12. The ophthalmoscope of claim 1, further including a wavelength varying mechanism for successively illuminating a portion of the subject'"'"'s retina by infrared radiation having two different wavelengths to obtain two electro-optical images wherein each image corresponds to a different one of said wavelengths.

13. The ophthalmoscope of claim 12, wherein each of said images is visually depicted by employing a distinct color, thereby increasing the contrast between the images.

14. The ophthalmoscope of claim 12, wherein said wavelength varying mechanism comprises two infrared sources having different radiation wavelengths.

15. The ophthalmoscope of claim 1, further comprising a filter for selectively filtering a predetermined spectrum of the radiation from said light source.

16. The ophthalmoscope of claim 15, wherein said predetermined spectrum includes the infrared spectrum.

17. The ophthalmoscope of claim 15, wherein said predetermined spectrum includes the visible spectrum.

18. The ophthalmoscope of claim 1, further comprising a filter for selectively filtering a predetermined spectrum of the reflected light from the interior of the patient'"'"'s eye.

19. The ophthalmoscope of claim 18, wherein said predetermined spectrum includes the infrared spectrum.

20. The ophthalmoscope of claim 18, wherein said predetermined spectrum includes the visible spectrum.

21. The ophthalmoscope of claim 1, wherein said light source includes an infrared source.

22. The ophthalmoscope of claim 1, wherein said light source includes a visible light source.

23. The ophthalmoscope of claim 1, wherein said light source includes a laser.

24. The ophthalmoscope of claim 1, wherein said imaging devices include a CCD.

25. The ophthalmoscope of claim 1, wherein said imaging devices include a LCD.

26. The ophthalmoscope of claim 1, wherein said imaging devices include a CRT.

27. The ophthalmoscope of claim 1, wherein said imaging devices include a camera tube.

28. The ophthalmoscope of claim 1, wherein said imaging devices include an image tube.

29. The ophthalmoscope of claim 28, wherein said image tube is an image intensifier.

30. The ophthalmoscope of claim 1, further comprising a processor for processing said images of the interior of the patient'"'"'s eye.

31. An improved ophthalmoscope, the improvement comprising:

a radiation source for illuminating the interior of a patient'"'"'s eye, and

imaging devices for electro-optically converting non-visible radiation reflected from the interior of the patient'"'"'s eye in response to said illuminating radiation to a binocular visible display thereof.

32. The improved ophthalmoscope of claim 31, further including an optical fiber coupled to said radiation source for directing light to the interior of the patient'"'"'s eye.

33. The improved ophthalmoscope of claim 31, further comprising a viewing assembly for receiving the radiation reflected from the interior of the patient'"'"'s eye and for directing a portion of said reflected radiation along two different optical paths to said imaging devices.

34. The improved ophthalmoscope of claim 31, further comprising a filter for selectively filtering a predetermined spectrum of the radiation from said radiation source.

35. The improved ophthalmoscope of claim 34, wherein said predetermined spectrum includes the infrared spectrum.

36. The improved ophthalmoscope of claim 34, wherein said predetermined spectrum includes the visible spectrum.

37. The improved ophthalmoscope of claim 31, further comprising a filter for selectively filtering a predetermined spectrum of the reflected radiation from the interior of the patient'"'"'s eye.

38. The improved ophthalmoscope of claim 37, wherein said predetermined spectrum includes the infrared spectrum.

39. The improved ophthalmoscope of claim 37, wherein said predetermined spectrum includes the visible spectrum.

40. The improved ophthalmoscope of claim 31, wherein said radiation source is an infrared light source.

41. The improved ophthalmoscope of claim 31, wherein said radiation source is a visible light source.

42. The improved ophthalmoscope of claim 31, wherein said imaging devices include a CCD.

43. The improved ophthalmoscope of claim 31, wherein said imaging devices include a LCD.

44. The improved ophthalmoscope of claim 31, wherein said imaging devices include a CRT.

45. The improved ophthalmoscope of claim 31, wherein said imaging devices include an image camera.

46. The improved ophthalmoscope of claim 31, wherein said imaging devices include an image tube.

47. The improved ophthalmoscope of claim 46, wherein said image tube in an image intensifier.

48. The improved ophthalmoscope of claim 31, further comprising a processor for processing the image corresponding to the binocular visible display of the interior of the patient'"'"'s eye.

49. A binocular ophthalmoscope comprising

a light source for illuminating the interior of a patient'"'"'s eye with light of a desired spectrum,

a viewing assembly for receiving light reflected from the interior of the patient'"'"'s eye in response to said illuminating light and directing along two optical paths a portion of said reflected light,

first and second imaging sensors, each of said sensors being placed in a different one of the two optical paths,

first and second lenses for focusing said portion of said reflected light onto said first and second imaging sensors, respectively, whereby said first and second imaging sensors produce first and second electrical signals, respectively in response to said focused reflected light, and

first and second displays responsive to said first and second electrical signals, respectively, for converting said first and second electrical signals into first and second visible display images of the interior of the patient'"'"'s eye, said visible display images being associated with the images of the interior of the patient'"'"'s eye taken along said two optical paths.

50. The binocular ophthalmoscope of claim 49, wherein said light source includes an infrared source of radiation.

51. The binocular ophthalmoscope of claim 49, wherein said light source includes a visible source of radiation.

52. The binocular ophthalmoscope of claim 49, further comprising a filter for selectively transmitting a predetermined spectrum of the light from said light source.

53. The binocular ophthalmoscope of claim 52, wherein said predetermined spectrum is in the visible spectrum.

54. The binocular ophthalmoscope of claim 52, wherein said predetermined spectrum is in the infrared spectrum.

55. The binocular ophthalmoscope of claim 49, further including an intensity modifier for adjusting the intensity of said light with a desired spectrum.

56. The binocular ophthalmoscope of claim 49, wherein said viewing assembly includes a pair of reflective elements spaced apart perpendicular to the direction in which the reflected light from the patient'"'"'s eye is propagating.

57. The binocular ophthalmoscope of claim 49, wherein said first and second imaging sensors are CCDs.

58. The binocular ophthalmoscope of claim 49, wherein said first and second imaging sensors are image cameras.

59. The binocular ophthalmoscope of claim 49, wherein said displays are LCDs.

60. The binocular ophthalmoscope of claim 49, wherein said displays are CRTs.

61. The binocular ophthalmoscope of claim 49, further comprising a filter for selectively filtering a predetermined spectrum of the light reflected from the interior of the patient'"'"'s eye.

62. The binocular ophthalmoscope of claim 49, further comprising a processor for signal processing said first and second electrical signals.

63. An indirect ophthalmoscope comprising

a light source for illuminating the interior of a patient'"'"'s eye with light,

an image intensifier having a fluorescent screen and a photosensitive surface, said fluorescent screen reproducing thereon an image corresponding to that formed on the photosensitive surface by light being focused on said surface, and

a lens for focusing on said photosensitive surface an image of an aerial image of the patient'"'"'s eye formed from light being reflected from the interior of the patient'"'"'s eye in response to said illuminating light.

64. The ophthalmoscope of claim 63, wherein said image intensifier converts non-visible radiation incident on the photosensitive surface to a visible display on the fluorescent screen.

65. The ophthalmoscope of claim 63, wherein the non-visible radiation is infrared radiation.

66. The ophthalmoscope of claim 63, further including an optical fiber coupled to said light source for directing light to the interior of the patient'"'"'s eye.

67. The ophthalmoscope of claim 63, further comprising a filter for selectively filtering a predetermined spectrum of the light from said light source.

68. The ophthalmoscope of claim 63, further comprising a filter for selectively filtering a predetermined spectrum of the reflected light from the interior of the patient'"'"'s eye.

69. The ophthalmoscope of claim 63, wherein said light source includes an infrared light source.

70. The ophthalmoscope of claim 63, wherein said light source includes a visible light source.

71. An ophthalmoscope comprising

a light source for illuminating the interior of a patient'"'"'s eye with light,

first and second image intensifiers, each having a fluorescent screen and a photosensitive surface, each fluorescent screen reproducing thereon an image focused on the corresponding photosensitive surface, and

first and second lenses for focusing on each photosensitive surface of said first and second image intensifiers, respectively an image of the interior of the patient'"'"'s eye formed from light being reflected from the interior of the patient'"'"'s eye in response to said illuminating light, each of said images of the interior of the patient'"'"'s eye taken along two different optical paths.

72. The ophthalmoscope of claim 71, wherein each of said first and second image intensifiers converts non-visible radiation incident on the photosensitive surface to a visible display on the fluorescent screen.

73. The ophthalmoscope of claim 71, wherein the non-visible radiation is infrared radiation.

74. The ophthalmoscope of claim 71, further including an optical fiber coupled to said light source for directing light to the interior of the patient'"'"'s eye.

75. The ophthalmoscope of claim 71, further comprising a filter for selectively filtering a predetermined spectrum of the light from said light source.

76. The ophthalmoscope of claim 71, further comprising a filter for selectively filtering a predetermined spectrum of the reflected light from the interior of the patient'"'"'s eye.

77. The ophthalmoscope of claim 71, wherein said light source includes an infrared light source.

78. The ophthalmoscope of claim 71, wherein said light source includes a visible light source.