Scientists, clinicians, and engineers from around the world gathered at OHSU’s Casey Eye Institute in July for the first international Optical Coherence Tomography (OCT) Angiography Summit. Participants spent the day sharing their knowledge and discussing applications of a pioneering imaging technology that has the potential to transform how we diagnose and treat patients with common causes of blindness, such as macular degeneration, glaucoma, and diabetic retinopathy.
James Fujimoto, Ph.D., was the summit’s distinguished guest speaker, discussing ultra-high-speed OCT angiography. Fujimoto was a co-inventor of the first OCT system with OHSU’s David Huang, M.D., Ph.D., and is a leading expert in OCT imaging. Some of the editors of the recently published Clinical OCT Angiography Atlas – Bruno Lumbros, M.D., of Italy, Andre Romano, M.D. of Brazil, Huang and Yali Jia, Ph.D., both of Casey Eye Institute – were also in attendance to discuss their work.
Using light waves to view the inner eye
OCT angiography is a noninvasive imaging technique for visualizing and measuring blood flow in the back of the eye. The device uses infrared light waves to capture detailed cross-sectional images of the retina’s layers. It can visualize the smallest defects in the tiny blood vessels in the eye. By contrast, conventional OCT allows physicians to view fluid and swelling in the retina, but not the abnormal vessels that are the hallmarks of severe macular degeneration and diabetic retinopathy. Another method – fluorescein angiography – can illuminate these miniscule but destructive vessels, but requires intravenous injection of a contrast dye. Dye-based angiography has its drawbacks, however, causing side effects such as nausea and vomiting. It can also obscure views of the retina’s inner layers should the dye leak or cause staining.
Casey Eye Institute: Exploring a new era in imaging technology
The Casey Eye Institute was a natural host for the OCT summit. Casey Eye faculty member David Huang, M.D., Ph.D., Peterson Professor of Ophthalmology in the OHSU School of Medicine, co-invented the first OCT system in the 1990s. His research lab has been testing software they developed called split-spectrum amplitude-decorrelation angiography algorithm (SSADA). Used with newer ultrafast OCT devices, this technology can map out the eye’s smallest capillaries and measure blood flow in about three seconds with high resolution. With fluorescein angiography, it takes 10 minutes.
Their lab, along with other study centers around the world, is testing OCT angiography with SSADA and comparing it to dye-based tests, They recently published research demonstrating that SSADA-based OCT angiography has advantages over dye-based methods for managing eye disease. In July, they showed that glaucoma can also be better managed by using this technology to study blood flow in the back of the eye.
Casey Eye investigators continue to explore new ways to refine OCT angiography using SSADA. OHSU has filed patent applications for the SSADA invention, which is licensed to a commercial company and is already being used clinically by physicians outside the U.S. It is also being used for research in the U.S., where it awaits FDA approval for wider application.
