Design of a Smartphone-Based Clinical Electroretinogram Recording System

Neurological disorders are a leading cause of disability worldwide, affecting millions of people. Early diagnosis is crucial for maximizing patient outcomes. This paper presents the design and development of a novel, smartphone-based light-adapted electroretinography (LA-ERG) device to capture ERG signals, a potential biomarker for various neurological disorders. This device offers a more affordable and accessible solution compared to traditional ERG equipment. The device leverages the smartphone camera to determine pupil diameter, eliminating the need for separate pupil dilation procedures, and delivers the correct flash intensity for precise control of light stimulation. It incorporates adjustable light stimulation, pupil diameter measurement using invisible infrared light, real-time signal processing, and Bluetooth Low Energy (BLE) communication between the smartphone and the device. Flash intensity can be adjusted within the smartphone app, and the approach enables real-time calibration of flash intensity based on pupil diameter measurements. The device captures 120 ms of the ERG waveform, including a 20 ms pre-stimulus baseline. The BLE interface successfully transmits information every 25 ms without data loss. Future work will focus on refining the usability of the device, validating its accuracy in clinical settings, and exploring its applicability to the diagnosis of various neurological and retinal diseases. This widely available and potentially cost-effective tool has the potential to revolutionize the early diagnosis of neurological disorders, paving the way for improved patient outcomes.