The new eye sensors use a special material that generates electricity when it bends

A team of engineers at the University of Houston has developed wearable sensors that can monitor eye movements to assess brain disorders or brain injuries. Many brain diseases and problems manifest with eye symptoms, often before other symptoms appear.

Eyes are not just a window to the soul, as poets claim. These incredibly valuable organs are also an extension of the brain and can provide warning signs of brain-related disorders and information about their causes. Eye examinations can also help track the progression and symptoms of physical and mental shocks to the brain.

Researchers say current eye-tracking systems are flawed and do not provide enough data. They are also bulky, have multiple electrodes on the face and neck, are expensive and have poor results.

The new method, developed in the UH lab by Jae-Hyun Ryou, associate professor of mechanical engineering, with help from postdoctoral researcher Nam-In Kim, is noninvasive, comfortable to wear and safe, allowing easy, continuous measurements and monitoring of eyeball movements when combined with a wearable display and computing device.

The new sensors are sleek and flexible, made of a very thin, crystal-like film that generates electricity when it bends or moves. This is a phenomenon called the piezoelectric effect, which allows certain materials to generate an electrical charge in response to applied mechanical stress.

The output voltages from the upper, middle, and lower sensors or transducers located on different areas of the temples generate discernible voltage patterns.

“Wearable sensors to be attached to the skin to monitor vital signs and biomedical parameters are components of great importance in personal healthcare and portable diagnostic systems,” Ryou reports in Advanced health materials.

“Among them, thin-film piezoelectric sensors offer unique advantages: easy manufacturing at low cost, wide range of available sizes, light weight, excellent mechanical flexibility and stability, fast reaction speed, high sensitivity, high signal-to-noise ratio, and excellent long-term stability and durability.”

“The new sensors are easy to wear and can be used in brain-eye relationship studies to assess the functional integrity of the brain,” he said.

Special attention paid to the disease

Ophthalmologic assessments of eye blink patterns have been used for early diagnosis of disorders such as stroke, multiple sclerosis, Parkinson’s disease, and Alzheimer’s disease. In addition, eye movements are closely related to various brain disorders, as the commands of the eyeball and upper eyelid are affected by brain function.

In previous studies, abnormal blink frequency and blink modulation have been measured in children with attention deficit hyperactivity disorder, with spontaneous blinking being a measure of the integrity of the brain’s dopamine system. Motor neurons in the brain, which are linked to the eyes and their muscles, have also been associated with autism.

“We believe that F-PEMSA can be used in many clinical studies for brain disorders such as ADHD, autism, Alzheimer’s disease and Parkinson’s disease, as well as sequelae of traumatic brain injury such as post-concussion syndrome and post-traumatic stress disorder, potentially offering the prospect of early and accurate diagnoses and the development of personalized therapies,” Ryou said.