Scientists, clinicians and engineers from throughout the world gathered at OHSU Casey Eye Institute for the first-ever international Optical Coherence Tomography (OCT) Angiography Summit. Participants spent the day sharing their knowledge and discussing applications of a breakthrough imaging technology that is transforming the way we diagnose and care for patients with the most common causes of blindness, namely macular degeneration, glaucoma and diabetes. OCT angiography is a noninvasive imaging technique proving to be a superior alternative to dye-based methods for visualizing and measuring blood flow in the back of the eye.

Using light waves to view the inner eye

OCT is considered one of the most significant advances in ophthalmic imaging and the most commonly ordered test for detecting and monitoring eye disease.  The device uses infrared light waves to capture detailed cross-sectional images of the retina’s layers. With conventional OCT, physicians can view fluid and swelling in the retina, but not the abnormal vessels that are the hallmarks of severe macular degeneration and diabetic retinopathy. Only fluorescein angiography, which requires intravenous injection of a contrast dye, can illuminate these miniscule but destructive vessels. However, dye-based angiography has its drawbacks, causing side effects such as nausea and vomiting, and obscuring views of the retina’s inner layers should the dye leak or cause staining.

A new era in imaging technology

As co-inventor of the first OCT system in the 1990’s, I am always searching for new and better ways to use this imaging tool. For the past several years, our research lab has been testing software we developed called split-spectrum amplitude-decorrelation angiography algorithm (SSADA). Used with newer, ultrafast OCT devices, this pioneering 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.

Our lab, along with other study centers around the world, are testing OCT angiography with SSADA and comparing it to dye-based tests. Research we recently published in the Proceedings of the National Academy of Sciences (PNAS) found that SSADA-based OCT angiography has considerable advantages over dye-based methods for managing eye disease. This month, we published another study in JAMA Ophthalmology showing that glaucoma can be better managed by using this technology to study blood flow in the back of the eye. 

Because OCT angiography is faster, better, safer and less expensive, we expect it will be frequently used for routine check-ups and to evaluate whether treatments are working. It also has great potential to pick up on eye problems too early to find in a clinical exam.

Interest in OCT angiography, as evidenced by the enthusiasm at this summit, is soaring. 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.

Our investigators continue to explore new ways to refine OCT angiography using SSADA. This new era of imaging technology will surely lead to better management of eye disease, helping preserve vision in millions of people here and abroad.

Learn more about OCT Angiography by viewing this video

David Huang, M.D., Ph.D., is Peterson Professor of Ophthalmology, OHSU School of Medicine, OHSU Casey Eye Institute, where he leads the Center for Ophthalmic Optics and Laser. Known for his innovations in applying laser and optical technology to eye diseases, he received the prestigious Champalimaud Vision Award in 2012 for his central role in co-inventing OCT. He also is a recipient of the ARVO Jonas Friedenwald Award, and the Senior Achievement Award from the American Academy of Ophthalmology.