Second Sight Medical Products, Inc.

The Salk Institute for Biological Studies

Doheny Eye Institute

Ione Fine

Robert Jay Greenberg

Matthew J McMahon

Alan Matthew Horsager

Arup Roy

Scott Greenwald

Mark Salman Humayun

Geoffrey M Boynton

Jessy D Dorn

Devyani Nanduri

Kelly Hobart McClure

Avraham I Caspi

James David Weiland

Rongqing Dai

Dao Min Zhou

Sumit Yadav

Amy Hines

Mark S Humayun

Alan Horsager

Matthew Mcmahon

Mathew Mcmahon

The present invention is a fitting system with a graphical interface with specific interface screens for specific functions. 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.

Visual prosthesis fitting

A visual prosthesis must convey luminance information across a range of brightness levels to accurately represent a visual scene. Thus, the brightness of phosphenes produced by individual electrodes should scale appropriately with luminance, and the same luminance should produce equivalently bright phosphenes across the entire electrode array. Given that the function relating current to brightness varies across electrodes, it is necessary to develop a fitting procedure that will permit brightness to be equated across an entire array. A visual prosthesis that generates stimuli by performing a brightness fitting that normalizes brightness across electrodes is described.

Fitting of brightness as a function of current amplitude in a visual prosthesis

Here we present the first model that quantitatively predicts the apparent spatial position and shape of percepts elicited by retinal electrical stimulation in humans based on the known anatomy of the retina. This model successfully predicts both the shape of percepts elicited by single electrode stimulation and the shape and relative positions of percepts elicited by multiple electrode stimulation. Model fits to behavioral data show that sensitivity to electrical stimulation is not confined to the axon initial segment, but does fall off rapidly with the distance between stimulation and the initial segment. Using the model, it is possible to compensate, preferably with a look up table, to match percepts to a desired image.

Method and apparatus for predicting and controlling the percepts induced by a visual prosthesis

The present invention is a visual prosthesis for stimulating visual neurons to create the perception of light. The visual prosthesis electrically stimulating the retina with implanted electrodes exhibits interaction between electrodes stimulated closely together in both space and time. The visual prosthesis of the present invention includes means for determining a minimum distance at which spatiotemporal interactions occur, determining a minimum time at which spatiotemporal interactions occur, and avoiding stimulation of electrodes within the minimum distance during the minimum time. The minimum are ideally established for each individual patient. Alternatively, approximate minimums have been established by the applicants at 2 mm and 1.8 milliseconds.

Multi-electrode integration in a visual prosthesis

The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual patient. The perceptual response to electrical neural stimulation varies from patient to patient and The response to electrical neural stimulation varies from patient to patient and the relationship between current and perceived brightness is often non-linear. It is necessary to determine this relationship to fit the prosthesis settings for each patient. It is advantageous to map the perceptual responses to stimuli. The method of mapping of the present invention is to provide a plurality of stimuli that vary in current, voltage, pulse duration, frequency, or some other dimension; measuring and recording the response to those stimuli; deriving a formula or equation describing the map from the individual points; storing the formula; and using that formula to map future stimulation.

Fitting of brightness in a visual prosthesis

To accurately represent a visual scene a visual prosthesis must convey luminance information across a range of brightness levels. To do this, the brightness of phosphenes produced by an individual electrode should scale appropriately with luminance, and the same luminance should produce equivalently bright phosphenes across the entire electrode array. Given that the function relating current to brightness varies across electrodes, it is necessary to develop a fitting procedure that will permit brightness to be equated across an entire array. The current invention describes a method of performing a brightness fitting that normalizes brightness across electrodes. The method determines a set of parameters that are stored in the subjects Video Configuration File&#x2014;the look-up table that converts the video camera input to stimulation profiles for each electrode. One electrode would be specified as the standard. Brightness rating would be carried out on that electrode so 'rating' as a function of current amplitude was known for that electrode.

The present invention is a method of stimulating visual neurons to create the perception of light. A visual prosthesis electrically stimulating the retina with implanted electrodes exhibits interaction between electrodes stimulated closely together in both space and time. The method of the present invention includes determining a minimum distance at which spatiotemporal interactions occur, determining a minimum time at which spatiotemporal interactions occur, and avoiding stimulation of electrodes within the minimum distance during the minimum time. The minimum are ideally established for each individual patient. Alternatively, approximate minimums have been established by the applicants at 2 mm and 1.8 &#x3bc;sec.

Methods of electrically stimulating percepts in a patient with a visual prosthesis are discussed. Changes in amplitude of stimulation increase both the perceived brightness and the perceived size of the precept. Changes in frequency of stimulation change the perceived brightness without altering the perceived size of the percept. Hence, a source image may be mapped to a combination of amplitude and frequency that best induces the desired image.

Encoding of size and brightness of percepts in a visual prosthesis

An apparatus and method for retinal stimulation are shown. The method comprises varied parameters, including frequency, pulse width, and pattern of pulse trains to determine a stimulation pattern and neural perception threshold, and creating a model based on the neural perception thresholds to optimize patterns of neural stimulation.

Apparatus and method for electrical stimulation of human neurons

An apparatus and method for retinal stimulation are shown. The method comprises varied parameters, including frequency, pulse width, and pattern of pulse trains to determine a stimulation pattern and visual perception threshold.

Apparatus and method for electrical stimulation of human retina

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.

The invention is a method of automatically adjusting an electrode array to the neural characteristics of an individual subject. The response to electrical neural stimulation varies from subject to subject. Measure of impedance may be used to predict the electrode height from the neural tissue and, thereby, predict the threshold of perception. Alternatively, electrode height may be measured directly to predict the threshold of perception. Also, impedance measurement may be used to quickly identify defective electrodes and proper electrode placement.

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