Retinal specialist Michael P. Teske, MD, has been an early adopter of optical coherence tomography angiography (OCTA), a developing technology that produces detailed 3D images of the retinal and choroidal vascular systems without the use of dyes.
We asked him to share how he’s using OCTA and the benefits this advanced imaging provides for patients.
How does OCTA differ from other imaging modalities you typically use?
What OCTA is doing is looking at microvasculature and blood flow in the retina, as well as to the optic nerve. We have imaged the vessels in the retina for many years, but it’s always involved more invasive and time-consuming studies. We have to use fluorescein or indocyanine green angiography, which both involve intravenous dyes. There’s a little more risk involved; some people get allergic reactions to the dyes. It's also time consuming, taking 20-30 minutes, since patients need an IV. OCTA is noninvasive and takes just a few minutes, and doctors can look at the microvasculature in a 3D fashion. These kinds of images are not attainable in standard angiography.
For what types of cases are you finding OCTA analysis most useful?
Most of what we treat in the retina these days—diabetic retinopathy, macular degeneration, post vein occlusions, macular telangiectasia—are things that alter the blood flow or blood vessels of the retina, so imaging the blood vessels is a very important part of what we do. OCTA enables us to do this imaging quickly and noninvasively, which is easier on patients and a fraction of the costs of other tests. The two things I use it for most are macular degeneration and diabetes. With macular degeneration, OCTA helps me detect if there is leakage, and if the vessels regressed or are still present.
This helps me decide if I need to continue treatment or watch the vessels more closely. In diabetes, it really helps us look at what’s happening even before there are any vision changes on a clinical exam. You’ll start to see changes in little capillaries very early using OCTA.
How do you see OCTA fitting into your practice in the future?
We’re still learning about it. We’re still imaging different types of diseases. For example, we’re in the early stages of how it will be used in glaucoma. The quality and resolution are getting better and better. With things like diabetic retinopathy, when you want to look at the blood vessels in the macula, OCTA has become the standard angiogram in just a couple of years.
The downside is if you want to look at the peripheral part of the retina, it’s still not doable. OCTA also doesn’t work for some patients. OCTA detects blood vessels by the motion of the blood cells through the blood vessels, so patients have to hold relatively still. If they are moving, the machine detects that as motion, and it can give you an artifact. Some patients have tremors or can’t hold their eyes still, and you might not get a very good study.
For now, it’s sort of revolutionized the way we look at circulation in the retina, to be able to do it very quickly and very easily, inexpensively, non-invasively. Is it a game-changer? Not yet, but neither was OCT when it first came out. Now there’s barely a patient I see that I don’t use OCT. I would guess as the machines are upgraded and become more common over the next few years, we’ll see OCTA technology used more and more and more.
About the Author
Dr. Teske is Moran's director of Vitreoretinal Diseases and Surgery.