Abstract
Purpose :
Electroretinography (ERG) remains an underutilized clinical diagnostic tool due to high device cost, complex testing procedures, and strict facility requirements. We performed a proof of concept study to explore the feasibility of a wearable medical device that isolates each eye independently while performing clinical grade ERG testing with the goal of decreasing per-procedure cost, time, and facility requirements in order to expand access to ERG testing.
Methods :
Device components were designed virtually using Computer Aided Design (CAD) software and 3D printed with black polylactic acid (PLA) thermoplastic polyester. Eye-pieces were made of polyurethane foam and designed for independent eye isolation from all environmental light. Red, green, blue, white, and infrared (IR) LEDs stimulate the retina and illuminate the IR camera. Light intensity is controlled via current and voltage regulators as well as pulse width modulation (PWM). Light stimulus duration is controlled via LED drivers. IR cameras dynamically measure pupil diameter and digitally adjust light intensity using PWM. A phototransistor measures the light stimulus being presented to each eye. EasyEDA and JLCPCB were used for printed circuit board (PCB) design and manufacturing. User interface, testing procedures, and image processing were programmed using a Raspberry Pi 4 and Python. Light intensity calibration was performed using a factory calibrated Internation Light Technologies 2400 Optical Meter. Pupil measurement calibration was performed using known diameter standards and validated on members of the research team.
Results :
See attached photos of prototype goggle device with attached LED control board as well as IR picture of eye with pupil measurements. The pupil measurement software was accurate within 2.5% relative to standard controls ranging from 4-26 mm. The estimated cost of this device, not including labor or excess materials, is $450.
Conclusions :
This rudimentary prototype is a preliminary proof-of-concept for a wearable ERG-device that reduces the cost, time and facility burdens associated with clinical ERG testing. Such a device would be particularly useful for early detection and monitoring of chronic disease states, such as diabetic retinopathy. Future directions include device fit optimization and incorporating skin electrodes and appropriate electrical amplifiers to measure the retinal response to light stimulation.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.