University of Houston develops advanced wearable eye-tracking sensors

A University of Houston engineering team has developed wearable sensors to examine eye movement for assessing brain disorders or damage. Many brain diseases manifest as eye symptoms, often before other signs appear.

"Eyes are not merely a window into the soul," said researchers. "These organs are an extension of the brain and can provide early warning signs of brain-related disorders and information on what causes them." Examining the eyes can also help track the progression and symptoms of physical and mental shocks to the brain.

Current eye-tracking systems have flaws, including insufficient data delivery, bulkiness with multiple electrodes on the face and neck, high costs, and weak outputs.

The new wearable sensors developed by UH engineers aim to address these issues. The sensors are non-invasive, comfortably wearable, and safe, enabling easy and continuous measurements when combined with a hand-held display and computing device. Developed in the lab of Jae-Hyun Ryou, associate professor of mechanical engineering, with assistance from Nam-In Kim, post-doctoral researcher, these sensors are made from thin crystal-like film that generates electricity when it bends or moves—a phenomenon known as piezoelectricity.

The output voltages from upper, mid, and lower sensors on different temple areas generate discernable patterns of voltage. "Skin-attachable wearable sensors for monitoring vital signs and biomedical parameters are components of great importance in personal healthcare and portable diagnostic systems," reported Ryou in Advanced Healthcare Materials.

"Among them, thin-film piezoelectric sensors offer unique advantages: easy fabrication at low cost, a wide range of available sizes, lightweight design, excellent mechanical flexibility and stability, rapid reaction rate, high sensitivity, high signal-to-noise ratio, and excellent long-term stability."

"The new sensors are easy to wear and can be used in brain-eye relationship studies to evaluate the brain’s functional integrity," he added.

Ophthalmological assessments of eye blinking patterns have been used for early diagnosis of disorders such as stroke, multiple sclerosis (MS), Parkinson’s disease (PD), and Alzheimer’s disease (AD). Ocular movements are strongly linked to various brain disorders since eyeball and upper eyelid controls are affected by brain function.

In former studies led by Ryou's team aberrant blink rate was measured in children with attention-deficit hyperactivity disorder (ADHD), using spontaneous blinks as a measure of dopaminergic system integrity in the brain. Motor neurons related to eyes have also been associated with autism.

"We believe that F-PEMSA can be employed in many clinical studies concerning conditions such as ADHD autism Alzheimer's disease Parkinson's disease post-concussion syndrome post-traumatic stress disorder potentially offering early accurate diagnoses personalized therapies," said Ryou.