Retina imaging spots signs of traumatic brain injury

05 Dec 2023

University of Birmingham EyeD device combines Raman spectroscopy and fundus imaging.

A project at the University of Birmingham could help identify the signs of traumatic brain injury (TBI) before other symptoms manifest themselves.

As published in Science Advances the technique is said to be dramatically different from other diagnostic methods, and suitable for development into a hand-held device used in the critical first "golden hour" after TBI when vital decisions on treatment must be made.

No point-of-care technology exists for quantitative assessment of TBI with sufficient sensitivity and timeliness to aid early diagnosis, whether at pitchside in contact sports or the roadside after motor vehicle collisions, noted the project in its paper.

"Early diagnosis of TBI is crucial, as life-critical decisions on treatment must be made with the first golden hour after injury," said Pola Goldberg Oppenheimer from the University of Birmingham.

"However current diagnostic procedure relies on observation by ambulance crews, and MRI or CT scans at a hospital which may be some distance away."

The Birmingham solution involves spectroscopic analysis of the neuroretina and optic nerve at the back of the eye. Since this region is a projection of brain tissue and clinically accessible through the pupil, it provides a window into the biochemistry of the brain.

In particular it can allow clinicians to detect biomarkers associated with TBI, including specific proteins or structural changes in lipids due to tissue damage. Both qualitative and quantitative assessment of these biomarkers is valuable for assessment of TBI and its severity.

Raman spectroscopy is known to be capable of spotting these biomarkers, but applying it as a golden-hour point of care technique for TBI has been hindered by the need for complex compound lens arrangements, required to accommodate both the high-magnification high-numerical aperture lens needed for Raman spectroscopy and the natural lens of the eye itself.

Crucial insight into diagnosis and monitoring

The team's solution is a portable and non-invasive imaging platform christened EyeD, which combines Raman spectroscopy with fundus imaging of the neuroretina. In use, a fundus image captured using the flash from a smartphone attached to the device allows visual identification of areas of interest, which can then be illuminated by laser for Raman analysis.

"Our unique device permits simultaneous Raman spectroscopy and fundus imaging by isolating the Raman and white light paths," noted the team in its paper. "EyeD consists of the combined fundus imaging optical path and eye-safe Raman spectroscopy path contained within a 3D-printed housing."

Crucially, the platform uses the eye's lens alone to focus a collimated beam onto the retina so that high-wave number Raman bands can be measured while simultaneously performing fundus imaging, removing the need for more complex lens requirements that has hindered point-of-care Raman ophthalmology previously.

An artificial neural network algorithm then interprets the collected data to distinguish healthy areas from those showing the chemical signatures of TBI biomarkers.

After trials on animal models, the project believes EyeD is now ready for further evaluation, including studies of clinical feasibility, efficacy and patient acceptability.

"The EyeD technology has the potential to offer crucial clinical insight in a growing number of diagnostic and patient-monitoring scenarios," commented the project. "This has the potential to revolutionize how TBI and neurological conditions are diagnosed and triaged."