Glaucoma is one of the world’s leading causes of irreversible blindness. Characterized by damage to the axons, the cable-like projections on neurons that transmit visual information from the eye to the brain, it’s linked to pressure changes inside the eye. 

But the glaucoma story is a bit more complex, involving the intricate role that mechanical forces play on the optic nerve, causing it to deteriorate and permanently impact vision. That’s the story Michaël Girard shared with his audience at the Coulter BME Seminar, Friday, Jan. 17, in the Health Sciences Research Building (HSRB II) at Emory University.

"The eye is not just an optical system,” said Girard, an Emory ophthalmologist and associate professor in the Wallace Coulter Department of Biomedical Engineering at Georgia Tech and Emory. “It’s a pressure vessel — it’s a mechanical system.”

As principal investigator of the Ophthalmic Engineering & Innovation Laboratory (OEIL), Girard guides a research team that uses cutting-edge imaging and computational modeling to study the mechanical forces underlying glaucoma. He launched OEIL in Singapore in 2012 and came to Coulter BME last year.

Accordingly, he spent his hour-long presentation telling the seminar audience (about 50, including online attendees) about his lab’s research program. Basically, the OEIL team develops and uses specialized engineering tools to better understand, diagnose, and treat eye diseases.

They combine basic science and translational research with an emphasis on three main areas: using artificial intelligence (AI) and deep learning for biomedical imaging; studying the biomechanics of the eye through experiments and simulations; and developing innovative ophthalmic devices and diagnostics.

Girard’s team uses advanced imaging techniques like optical coherence tomography (OCT) to visualize the structure of the optic nerve in unprecedented clarity, even tracing individual axon bundles. Combining this data with computer modeling, the researchers hope to find mechanical triggers — stress, compression, or bending — that lead to axon damage. 

"Ideally, we'd love to develop a mechanical test for the optic nerve, because it doesn't exist yet," Girard said. "Then we could assess the robustness of the back of the eye and identify who's at risk of rapid vision loss.”

The researchers are exploring various approaches to fill this gap, including gentle pressure tests on human volunteers — some seminar attendees expressed interest in volunteering. The idea is by studying how young and old eyes respond differently, Girard’s team can uncover the age-related changes in tissue mechanics that make the elderly more susceptible to glaucoma.

"Glaucoma is a disease that mostly affects the elderly — you're most likely to get it after age 50," Girard noted. "So, it's very important to understand the impacts of age as well."

Ultimately, Girard believes that cracking the mechanical code of glaucoma could lead to better ways to predict, prevent, and treat the disease. Also, the lessons learned may extend beyond the eye, informing our understanding of other neurological disorders.

"This is not just about glaucoma," Girard said. "It's about using engineering and physics to understand the biology of the nervous system."

The Coulter BME Seminar Series, held on a semi-regular basis, features research presentations from principal investigators and graduate trainees, including invited guests. Attendees from across Georgia Tech and Emory are invited.

Sitting front and center for Girard’s seminar was Hanjoong Jo, the John and Jan Portman Professor in the Coulter Department, based at Emory, where he heads the Cardiovascular Mechanobiology, Therapeutics, and Nanomedicine Lab. He left the seminar energized.

“I was impressed that Michaël is developing an exciting AI-based methodology to help predict who may develop glaucoma,” said Jo. “His work integrates state-of-the-art optical imaging in the clinic with his biomechanics expertise, and AI-based computational modeling. I think his work could provide a crucial early diagnostic tool for patients and clinicians to prevent the loss of eyesight due to glaucoma.”