Second Sight Medical Products, Inc.

Doheny Eye Institute

Devyani Nanduri

Robert Jay Greenberg

Jessy D Dorn

Ione Fine

Matthew J McMahon

James David Weiland

Mark Salman Humayun

Kelly Hobart McClure

Ashish Ahuja

Avraham I Caspi

Mark Humayan

Kelly H Mcclure

Avraham Caspi

The present invention is an improved method of stimulating visual neurons to create artificial vision. It has been found that varying current of visual stimulation can create varying percept brightness, varying percept size, and varying percept shape. By determining the attributes of predetermined current levels, and using those attributes to program a video processor, more accurate video preproduction can be obtained. The present invention also includes an electrode array having alternating large and small electrodes in rows at a 45 degree angle to horizontal in the visual field.

Visual prosthesis for phosphene shape control

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

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

This system gives the experimenter great flexibility to present spatio-temporal stimulation patterns to a subject. A video configuration file (VCF) editor allows the experimenter to determine the electrical stimulation parameters for each electrode. A Pattern Stimulation software program allows direct stimulation of chosen patterns of electrodes, scaled by the subject's VCF, through a Graphical User Interface. The subject then responds by drawing the outline of the phosphene he or she perceives on a touchscreen. The Pattern Stimulation program saves all of the trial parameters and the parameters of an ellipse fit to their drawing, as well as a raw data file containing the input to the touchscreen is saved. After the experiment, offline image analysis can be performed to obtain a detailed quantitative description of the subject's percepts. Image descriptors can assigned to the touchscreen data; these image descriptors can be used to make formalized comparisons between various experimental conditions. Various types of image descriptors can be used, including simple ellipse fitting, projections of the 2-D drawings onto one-dimensional axes, calculations of Hu moments, PCA, and ICA.

System and method for measuring and fitting spatio-temporal vision

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Los Angeles, CA, United States of America

Devyani Nanduri