EOG-controlled Visual Prosthesis Bree Christie, Ashley Godin, Umakanthan Kavin, Parth Sheth

Background Enucleation: Removal of entire eye Reasons for surgery: trauma, glaucoma, tumors, pain Replace with orbital implant and ocular prosthetic Common complication: loss of function in extraocular muscles Leads to less control over prosthetic device movement Prosthetic is more noticeable

Representation

Electrooculography (EOG) The eye acts as a dipole where the front is positive and back is negative Attributed to higher metabolic rate in the retina Position of the eye creates a voltage potential

Objective Goal: Use EOG signals from the natural eye to dictate movement of artificial eye model This would allow for natural movement of the artificial eye and lessen the visibility of the prosthetic

Approach

Pre-Breadboard Electrodes detect magnitude of potential and polarity of potential Polarity of potential will indicate direction Amplitude will be ~0.3 mV http://www.bem.fi/book/28/28.htm

Signal Conditioning Amplifier (gain ~ 300) Band-Pass Filter (0.5-10 Hz) Noise Decay

Block Diagram

LabVIEW Data Acquisition and Analysis 50 samples read at a rate of 1 kHz Results in a “refresh rate” of 50 ms for quasi-real-time output In-program band-pass filter of 0.5-40 Hz Signals were compared against selected thresholds and generated an output accordingly

Arduino and Servo Motor Control Arduino Uno microcontroller board (ATmega328) USB connection MATLAB control Servo motor: rotary motor allowing control of specific positions

Results & Validation

Signal Conditioning Results DC filtering will result in signal decays (bottom) Yellow is horizontal movement Blue is vertical movement (blinks) 1a 1b 2 3

Validation Achieved horizontal movement and blinks in animated computer model based on synchoronous natural eye EOG signals Demo

Questions