As a journalist who covers vision technology, I’ve become fascinated with eye tracking and its many uses, which range from health care to virtual and augmented reality, sports training, gaming, retail, marketing, education and military applications. Eye tracking uses motion-detecting sensors embedded in special eyeglasses or behind a computer screen to detect and measure eye movement. As many VMAIL readers know, it’s used for diagnosing and treating vision problems related to the eye-brain connection.

“We use eye tracking on virtually every single one of our patients who are coming in with a visual processing issue,” said Charles Shidlofsky, OD, FCOVD, a vision development and vision rehabilitation specialist whose practice, Neuro-Vision Associates of North Texas, is in Plano, Texas.

Dr. Shidlofsky, who is vice president of NORA (Neuro Optometric Rehabilitation Association), has been using various eye tracking methods for 25 years. He currently uses the RightEye system.

Dr. Shidlofsky offered a few examples of the types of patients who can benefit from eye tracking. “The first type of person is a child or anyone else who has any type of reading dysfunction. You'd also want to do eye tracking with any concussion patient. It’s super powerful. And I use it a lot of with my stroke patients, and also with athletes.”



AdHawk MindLink eye tracking glasses.


 
As researchers continue to develop and refine eye tracking technology, they’re learning more about the eye-brain connection. So when a four-year old Canadian tech startup called AdHawk Microsystems recently announced the launch of an eye tracking eyeglass called MindLink that promises to unlock new insights into visual function and perception, I was intrigued.








Illustrations show MindLink in position of wear (top) and location of scanner modules (bottom).
 
Touted by AdHawk as the fastest wearable eye tracking system available, MindLink produces accurate eye movement data to provide insights into human behavior, ocular, and neurological health. Delivered in the form of lightweight and comfortable glasses, MindLink can be worn comfortably to precisely measure eye movement, pupil size, and head movement using an integrated inertial measurement unit (IMU) sensor.

The superior data quality it produces enables researchers to advance the study of conditions like anxiety, ADHD, concussions, and epilepsy, while improving the assessment of cognitive load and reading challenges, according to AdHawk. The data gathered by MindLink will also assist in researching the progression of neurodegenerative conditions like Alzheimer’s and Parkinson’s disease, the company said.

“It's sort of like a Fitbit for mental health instead of cardiovascular health,” AdHawk CEO and co-founder Neil Sarkar, PhD, told me.

Unlike other eye tracking glasses, which typically use built-in cameras, MindLink uses ultra-compact micro-electromechanical systems (MEMS) that eliminate power-hungry image processing, significantly improving its speed and energy efficiency. The system is so fast it can accurately predict where a user will look next—up to 20 milliseconds before their eyes fixate—and gaze is captured 500 times per second with better than one degree of accuracy, according to AdHawk.

Watch a video about AdHawk Mindlink.



In addition to increased speed and precision, AdHawk offers physicians and researchers more flexibility, because they are not constrained by bulky products that can only be used in a lab environment. This means that physicians and researchers can now conduct eye tracking assessments in more settings than ever before, including a doctor’s office, in the field or in a patient’s home.

“The sampling frequency of an eye tracking system refers to how many times per second the position of the eyes is registered by the eye tracker. A greater sampling frequency improves a researcher’s ability to estimate the true path of the eye when it moves,” said Dr. Elizabeth Irving, professor with the School of Optometry and Vision Science at the University of Waterloo, which is working with AdHawk’s technology.

“Until now, a higher sampling frequency came at a higher cost because it required more expensive cameras and more power. This is what makes AdHawk’s system so special—they have found a way to deliver mobility, quality and speed—all without sacrificing affordability.”

Watch a video demonstration of a person’s visual behavior when driving a car while wearing MindLink.





MindLink is styled like conventional eyeglasses.


 
I asked Sarkar to give an example of how MindLink, and the data it generates, can benefit eyecare providers, such as neuro-optometrists. He replied, “Patients can just put these glasses on and start tracking right away to produce the accuracy, precision and bandwidth that are required for the research applications like detecting concussions, recovering from concussions and monitoring the recovery process.”

Sarkar noted that emergency room visits resulting from concussions are often related to dizziness, and that wearing a pair of MindLink glasses would enable doctors to gather data that would complement the patient's anecdotal description of how they feel. “If you decide to medicate them, you can send them home with these glasses and monitor the recovery from vertigo,” he said.

AdHawk’s technology could also be applied to ophthalmic lens design. “Let’s say you just got a new prescription for progressive lenses filled, and you have astigmatism,” said Sarkar. “There are certain things about human visual behavior that could indicate discomfort when, say, the sweet spot in your lens is too small, so you're only able to see things sharply in the central 10 degrees.




The lightweight glasses are comfortable enough to be worn all day, enabling extensive capture of eye tracking data.
 
“Anytime you make an eye movement greater than 10 degrees, you're going to rotate your head, along with it. So having an IMU inside the glasses that can measure head rotation along with the eye tracker could actually help companies improve their lens design. It could also help patients know how well their prescription works for them.”

Using eye tracking to customize a patient’s prescription is one reason that AdHawk has attracted the attention of Essilor International. The optical giant is one of several investors in the company, along with Samsung Venture Investment Corp, HP Inc., Sony Innovation Fund, Intel Capital, Brightspark Ventures and Silicon Valley Bank. As eye tracking technology continues to be developed by AdHawk and other companies, it is likely to become an even more valuable tool for optical researchers and eyecare practitioners.

“In the last five years, eye tracking has been revolutionized,” said Dr. Shidlofsky, the vision rehabilitation specialist. “As eye tracking technology keeps improving, we're going to get more and more accurate data. I think we're on the right track toward really making this a mainstay of eyecare.”

As eye tracking technology continues to be developed by AdHawk and other companies, it is likely to become an even more valuable tool for optical researchers and eyecare practitioners.


Denis Cohen-Tannoudji Outlines Essilor’s Eye Tracking Efforts

To find out more about Essilor’s interest in AdHawk’s eye tracking technology, I spoke with Denis Cohen-Tannoudji, senior vice president smart vision solutions, Essilor International.



Denis Cohen-Tannoudji


 
“The eye tracker is potentially an important technology to incorporate into smart glasses,” said Cohen-Tannoudji. “And, of course, smart glasses is a subject of interest for EssilorLuxottica.” In September 2020, the company announced a collaboration with Facebook that is expected to culminate in the launch of Ray-Ban smart glass this year.

Cohen-Tannoudji said eye tracking might also be incorporated into optometry instrumentation. He explained, “Typically, if we want to capture some data in an optical shop using a tablet or other device, we could use eye tracking in a specific way to measure some important parameters for dispensing customized lenses. This is the main reason why we think eye tracking is an important technology, and why we invested in AdHawk.”

Essilor is also studying other potential applications for eye tracking. “We have an R&D team in Paris that is working on neurovision science and optometry, so eye tracking is an object of interest for all of our eye-brain research,” said Cohen-Tannoudji. “To give you an example, we have sponsored an academic chair at the Paris University focusing on the aging of the visual system. It’s called Silversight. Some of their research involves eye tracking.”

As an aid to researchers, AdHawk has released the AdHawk MindLink kit, which it is offering at a discounted price of $3,500 until April 30, 2021 (after that, the kit will cost $10,000.) To pre-register for a kit, visit: https://adhawkmicrosystems.com/order. Kits are expected to ship within six to eight weeks of the presale closing date. Cohen-Tannoudji said Essilor is supplying a set of lenses of various powers to go with the kit.