Using the eye to measure the brain

3 minute read

Image of retinal scan

A prototype device for measuring intracranial pressure (ICP) is set to eliminate the need for brain surgery in head trauma patients, providing fast, non-invasive, critical decision-making data to clinicians to improve patient outcomes.

With philanthropic support from the Michael Hirshorn Medical Research Commercialisation Fund, Associate Professor Bang Bui has brought together a multidisciplinary team of experts at the Department of Optometry and Vision Sciences at the University of Melbourne to move the device into the next phase of development. The support has also provided for appointment of an Early Career Researcher to ensure the project remains sustainable over time, an important step in the commercialisation of a new device.

The device uses ophthalmodynamometry, or the measurement of blood pressure dynamics within the blood vessels in the eye, to reveal high pressure around the brain following physical trauma.

Such pressure can quickly lead to brain injury but measuring this pressure to determine life-saving action is traditionally only possible through invasive brain surgery, which takes time and presents the risk of infection and complications.

Time is of the essence

“When it comes to any trauma, but especially head trauma, we know time is of the essence. Many of the existing tools we rely on for diagnostics are not portable. A clinically viable device to be used for trauma patients must be handheld and portable and able to be used both in upright patients and those patients lying down.”

Having shown preliminary feasibility of this method, Bang Bui and his team now aim to develop a handheld device that can be used to calculate the correlation between vascular instability using ophthalmodynamometry and ICP in patients admitted to the Royal Melbourne Hospital due to head trauma.

“Design and manufacture of a desktop-based prototype has provided us with initial proof of concept. This prototype device has informed the design principles for a fully handheld system,” Bang Bui says.

The automated handheld ophthalmodynamometry unit will comprise a feedback force sensor to compensate for movement – allowing for use in a wide range of postures while processing images of retinal blood vessels.

The approach takes advantage of the fact that the pulsing of the blood vessels just as they leave the eye is influenced by the intracranial pressure (ICP) in the sheath surrounding the optic nerve just outside of the eye.

In addition to faster, non-invasive diagnosis, this new technique will significantly reduce the cost of monitoring ICP by eliminating the need for invasive surgery,” he said.

Associate Professor Bui and the team including Associate Professor Lauren Ayton, Dr Sam John, Professor David Grayden and Associate Professor Andrew Morokoff say support from the Michael Hirshorn Medical Research Commercialisation Fund has been essential to maintaining continuity in their research during COVID interruptions during 2020. Having the seed funding in place at the very beginning of 2020 meant they were able to collect substantial proof of concept data through the first quarter of 2020. This allowed them to develop image analysis approaches and to interpret the data through the second half of 2020.

Further work

“Having this pilot data reassured us of the commercial potential of this project. Our team has already submitted two grant applications to support clinical trials in hospital settings and use of the portable device in critical care field settings.

“We will continue to work to refine the device on laboratory eye models and healthy eyes, to ensure the system can be robustly used by clinicians.

Publication

L. Lo et al., "Non-Invasive Measurement of Intracranial Pressure Through Application of Venous Ophthalmodynamometry," 2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), 2021, pp. 6771-6774, doi: 10.1109/EMBC46164.2021.9629651.

Funding

The Michael Hirshorn Medical Research Commercialisation Fund (CI Bui)

University of Melbourne Seed Grant (CI Ayton)

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