Visual prosthesis fitting

• US 20070255343A1
• Filed: 04/27/2007
• Published: 11/01/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Cortigent Incorporated, Doheny Eye Institute
• Original Assignee: Doheny Eye Institute
• Inventors: Greenberg, Robert, Roy, Arup, Greenwald, Scott, Fine, Ione, Caspi, Avraham, McMahon, Matthew, McClure, Kelly, Horsager, Alan
• Granted Patent: US 8,271,091 B2
• Time in Patent Office: Days
• US Class Current: 607/54
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means

Abstract

Methods and devices for fitting a visual prosthesis are described. In one of the methods, threshold levels and maximum levels for the electrodes of the prosthesis are determined and a map of brightness to electrode stimulation levels is later formed. A fitting system for a visual prosthesis is also discussed, together with a computer-operated system having a graphical user interface showing visual prosthesis diagnostic screens and visual prosthesis configuration screens.

Claims

1. A method for fitting a visual prosthesis having a plurality of electrodes, the method comprising:

determining at least one level on a first electrode by patient feed back;

determining at least one other level for subsequent electrodes based on previous results and further patient feedback; and

creating and storing a map of brightness to electrode stimulation levels based on the established levels.

2. The method of claim 1, further comprising:

determining at least another level on the first electrode; and

determining at least one more level for subsequent electrodes based on previous results and further patient feedback.

3. The method of claim 2, wherein the at least one level and the at least one other level are threshold levels.

4. The method of claim 3, wherein the at least another level is a maximum level.

5. The method of claim 4, wherein the at least one more level is a maximum level.

6. The method of claim 4, wherein the maximum level is a level of three quarters of a safety limit.

7. The method of claim 4, wherein the maximum level is a maximum comfort level for the patient.

8. The method of claim 2, wherein the threshold level on the first electrode and subsequent electrodes is determined through a 150-750 ms train of 10-100 Hz pulses.

9. The method of claim 1, wherein one electrode among the first electrode and the subsequent electrodes is chosen as a standard electrode.

10. The method of claim 9, wherein the standard electrode is the electrode having a median threshold value.

11. The method of claim 9, wherein the patient is subjected to a brightness comparison between the standard electrode and each electrode different from the standard electrode.

12. The method of claim 9, wherein the patient is subjected to a brightness comparison by rating brightness of a clump of electrodes.

13. The method of claim 4, wherein the maximum level on the first electrode and subsequent electrodes is determined by gradually increasing an amplitude of stimulation pulses.

14. The method of claim 5, wherein determination of threshold and maximum levels on the electrodes is performed by converting a video camera input to a pattern of electrical stimulation.

30. A fitting system for a visual prosthesis, comprising:

a computer;

software, loaded in the computer, adapted to perform a fitting method for a visual prosthesis having a plurality of electrodes;

a video processing unit; and

a video module to download a video configuration file to the video processing unit, wherein the fitting method is a fitting method according to claim 1.

31. The fitting system of claim 30, wherein the fitting system is connected to a psychophysical test system.

15. A method for fitting a visual prosthesis having a plurality of electrodes, comprising:

providing a video camera associated with a pair of glasses;

capturing an image through the video camera;

sending the image to a video processing unit;

converting the image to a digital image;

processing the digital image to obtain a processed digital image; and

presenting the processed digital image to the retina of a subject by way of electrical stimulation, wherein the processed digital image comprises a plurality of intensity values scaled from black to white.

16. The method of claim 15, further comprising:

determining which parts of the processed digital image are mapped to individual electrodes of the visual prosthesis.

17. The method of claim 16, wherein a map of location of phosphenes generated by each electrode is determined and is then used to determine which sections of the processed digital image each electrode is mapped to.

18. The method of claim 17, wherein the location of the phosphenes is obtained by stimulating each electrode and asking the subject to place a reflective ball in the location of the phosphene.

19. The method of claim 18, wherein the location of the ball is a three-dimensional location measured through an infrared stereo camera system.

20. The method of claim 17, wherein the location of the phosphenes is obtained through interpolation techniques.

21. The method of claim 16, wherein a single intensity value is determined to be transmitted to the retina of the subject.

22. The method of claim 21, wherein the single intensity value is transmitted through an electrical stimulation protocol.

23. The method of claim 21, further comprising:

producing a perceptual brightness level corresponding to the single intensity value.

24. The method of claim 23, wherein production of the perceptual brightness level is produced with a technique chosen from:

varying pulse amplitude to control brightness, varying pulse frequency, varying pulse width, or direct modulation of ganglion cell output with electrical pulses of varying frequency.

25. The method of claim 16, wherein mapping to the individual electrodes is established by determining a first value to be mapped to a minimum image value for each electrode, a second value to be mapped to a maximum image value for each electrode, and further determining intermediate values.

26. The method of claim 25, wherein the first value, second value and intermediate value are pulse parameter values.

27. The method of claim 25, further comprising:

performing a comparison of values between neighboring electrodes.

28. The method of claim 15, wherein fitting is confirmed through testing of the subject.

29. The method of claim 28, wherein testing comprises at least one of:

a spatial resolution test, a brightness linearity test, an ophtalmic exam, a visual acuity test, a device performance test, a visual field test, an optical coherence tomography test, an electroretinogram test, fluorescein angiography, retinal photography, dark-adapted light perception, an electrically evoked response, a light projection test procedure, grating visual acuity, electrode impedance test, electrode threshold test, first stimulation procedure, vision and quality of life survey, Massof inventory, functional assessment of self reliance on tasks test, psychophysical test, spatial mapping of phosphenes, brightness matching, motion discrimination, flicker fusion, and orientation and mobility task.

32. A fitting system for a visual prosthesis, comprising:

a computer;

software, loaded in the computer, adapted to perform a fitting method for a visual prosthesis having a plurality of electrodes;

a video processing unit; and

a video module to download a video configuration file to the video processing unit, wherein the fitting method is a fitting method according to claim 15.

33. The fitting system of claim 32, wherein the fitting system is connected to a psychophysical test system.

34. A computer-operated system comprising a display component, the display component having a graphical user interface associated with a method for fitting a visual prosthesis having a plurality of electrodes, the graphical user interface comprising:

a visual prosthesis diagnostic screen; and

a visual prosthesis configuration screen.

35. The system of claim 34, wherein the diagnostic screen comprises an electrode impedance measurement screen.

36. The system of claim 34, wherein the diagnostic screen comprises a waveform measurement screen and a waveform viewer screen.

37. The system of claim 34, wherein the visual prosthesis configuration screen shows commands for operating a video application.

38. The system of claim 37, wherein the video application comprises a stimulation section, a video configuration section and a current configuration section.

39. The system of claim 34, wherein the visual prosthesis configuration screen shows commands for adjusting threshold parameters of the electrodes.

40. The system of claim 34, wherein the visual prosthesis configuration screen shows commands for adjusting brightness parameters.

41. A method for providing a direct measurement of individual phosphene locations within a video image, comprising:

stimulating a plurality of electrodes, each electrode producing a phosphene when stimulated;

asking a subject to locate the phosphenes; and

recording a subject'"'"'s location of the phosphenes in the video image.

42. The method of claim 41, wherein each electrode is stimulated with a direct stimulation controller.

43. The method of claim 41, said method being for correction of spatial distortions in a retinotopic map.