As any eye care professional knows, having the ability to thoroughly screen patients for retinal diseases, such as diabetic retinopathy and age-related macular degeneration (AMD), is extremely important. One of the newest products helping ophthalmologists and optometrists diagnose and manage these types of patients is the AngioPlex™ OCT Angiography from Zeiss.
What It Is
Zeiss' AngioPlex OCT (optical coherence tomography) Angiography is an imaging machine capable of taking 3D images of microvascular blood flow.
"It’s a non-invasive imaging technology that bounces light waves off different parts of the eye, giving a very high resolution image within seconds," explained Dr. Mary Green, president of Eye Excellence and chief of ophthalmology at CHI Baylor St. Luke’s Hospital, both in Houston. "It gives you what we call volumetric data with clinical applicability to specifically localize or delineate pathology in somebody’s retina or optic nerve because it shows both structural and blood flow information at the same time."
According to Dr. Amir Kashani, assistant professor of the USC Roski Eye Institute in the Keck School of Medicine at USC, OCT angiography is very similar to the standard OCT imaging that eye care professionals are used to seeing, however, it involves a different scan pattern thanks to software and hardware changes. "That different scan pattern allows us to look at the reflection of light from moving objects like red blood cells, versus static objects like the neurosensory retina, so we can detect the movement of very small particles without the injection of any dye,” he added. This, Kashani said, has significant benefits for patients, technicians and clinicians in the management of retinal vascular diseases such as diabetic retinopathy and retinal venous occlusions.
Patient Benefits
Green, who was one of the earliest adopters of the OCT angiography technology, is a general ophthalmologist and cornea refractive specialist who saw the AngioPlex as a better way of screening her diabetic patients for diabetic retinopathy and senior patients for AMD. “With OCTA, I can see microvasculature structures and areas of reduced blood flow,” she explains. “I can see little micro aneurysms — things that I couldn’t see with just a clinical exam and regular OCT.”
This, Green said, allows her to provide additional information to her diabetic patients' internists so they can similarly adjust medications as necessary. And for AMD patients, it can provide her with early information if a patient's condition is morphing from dry to wet AMD.
According to Kashani — who has been using OCT angiography prototypes on a research basis for almost three years and the Zeiss AngioPlex device on a clinical basis since its FDA approval in 2015 — OCT angiography is also allowing him to develop quantitative metrics of retinal vascular changes, which is a research focus of his lab. “Not only can we take pictures and show qualitatively where there’s presence or absence of blood flow, but we can actually start to quantify the capillary density, the branching patterns of the capillaries — things that we couldn’t do in patients in the past because the technology just wasn’t there,” he said. Kashani noted while the AngioPlex is FDA cleared, the quantitative metrics are still in development.
This quantitative information, Kashani added, will hopefully provide practitioners a new index of disease severity. “Now we can develop numbers that indicate the severity of the disease and it’s a more objective reflection of how bad or good the disease is,” he said. “I think that will really change the way we manage some of these diseases.”
Practice Benefits
When it comes to practice benefits, one that Kashani mentioned is how easy it is for both patients and technicians to use. For patients, he said the scans are fast, painless and essentially risk-free. And for technicians, the device is essentially the same as the previous Cirrus devices making learning and operating the machine simple.
However, Kashani said for clinicians there are some big differences as the OCT angiography data is very novel and presented differently than with a standard OCT. Kashani explained OCT angiography images are presented en face, and offer depth information not available from fluorescein angiograms. “The physician is going to appreciate a lot more detail about the retinal vasculature in these images, and also have a lot more information to digest at the same time,” he added.
For Green, because the AngioPlex does not require any dyes or injections such as with fluorescein angiography, the process is much simpler and allows her to take an OCTA scan of a patient every time they come to the office. "It does not diminish flow through the office, it’s very quick, and there is no risk to the patient," she added.
And Green said the images taken by the AngioPlex provide her with a great visual to explain to patients what it going on with their eye health. “We have a computer screen in all of our exam lanes and we just send the information over so the doctor can show each patient their pictures and what the pathology is or, in a lot of cases, the lack of pathology,” she said. “The patients really love to see that.”
Looking Ahead
Overall, Green said the AngioPlex makes her feel she's doing a better job in diagnosing and managing her patients with ocular vascular disease or vascular disease of the retina. Looking to the future, she is also planning to apply the technology to her glaucoma patients as it allows her to look at blood flow in the optic nerve.
As OCT Angiography and AngioPlex is a relatively new technology, Kashani said there are still new capabilities yet to discover. For instance, he said OCT angiography may be able to show different findings in rarer diseases and over the next two to five years it will help practitioners discover new avenues of disease management and progression. “We’ll probably be able to detect and diagnose diseases better than we did before,” he explained. “It’s not clear how that will be done exactly yet, but there’s already very good evidence that is going to happen in some way, shape or form.”
And this, Kashani said, will aid in the development of different kinds of therapies. "OCT angiography is going to allow us to see different anatomical features of the retina and measure the outcome of potential therapies much more effectively," he added. "That’s going to actually enable new therapies to be developed much more effectively than they could have been before."