BUFFALO, N.Y. — Modern life depends on quantum physics. It makes technologies such as GPS navigation, MRI scanners and computer chips possible.
Now, the same science may also lead to a new way to test the health of our eyes.
A University at Buffalo-led team has used a technique from quantum optics to make a little-known visual pattern produced inside the eye easier to see — potentially opening the door to a new way to test retinal health.
Known as Boehm's brushes, these faint, two-lobed, bowtie-shaped patterns sometimes appear in peripheral vision when polarized light scatters off structures in the retina. Because people with retinal disease may be less likely to perceive them, scientists have long wondered whether they could serve as a biomarker of retinal health.
However, Boehm's brushes are often too hard to see, even for people with healthy eyes, to be useful in clinical practice.
In a study published today (July 9) in the Proceedings of the National Academy of Sciences (PNAS), researchers used a specially engineered form of polarized light to enhance the perception of Boehm's brushes in about a dozen healthy volunteers.
"Our structured light transformed the normally faint, two-lobed bowtie patterns into brighter, easier-to-see ones with a variable number of lobes," says corresponding author Dusan Sarenac, PhD, assistant professor of physics in the UB College of Arts and Sciences. "The more complex patterns give us multiple ways to measure patients' perception of the phenomenon and, potentially, the health of their retinas."
The researchers used what's known as structured light, an engineered form of polarized light developed for quantum optics and used in microscopy and precision sensing. Unlike ordinary polarized light, its carefully arranged polarization pattern better matches the symmetry of structures in the retina.
When the structured light reached the retina, Boehm's brushes appear larger, brighter and more complex.
The experiments were done at the School of Optometry at the University of Waterloo. The participants viewed the structured light through an optical setup similar to a traditional eye exam and answered questions about what they saw. After each response, the system automatically adjusted the contrast, making the pattern easier or harder to see until it determined each participant's visual threshold.
"Instead of simply asking participants whether they saw Boehm's brushes, we measured how many lobes they saw, the contrast they needed to detect them and where the patterns appeared in their visual field," says first author Dmirtry Pushin, PhD, associate professor of physics at the University of Waterloo.
The researchers found that participants with healthy eyes detected the patterns more easily farther from the center of vision — an expected result that provides a baseline for future studies.
The next step, Sarenac says, is to test people with retinal diseases, such as macular degeneration. The goal would be to determine whether damaged areas of the retina change how they perceive the patterns.
The study was conducted in collaboration with the Centre for Eye and Vision Research (CEVR), a Hong Kong-based institute founded by Hong Kong Polytechnic University and the University of Waterloo. Before joining UB, Sarenac was a co-principal investigator at CEVR and a senior technical lead of transformative quantum technologies at the University of Waterloo's Institute for Quantum Computing.
This work was supported by the Natural Sciences and Engineering Research Council of Canada and the Canada First Research Excellence Fund.
