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OCT angiography will play role in managing choroidal retinal degeneration
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ATLANTA – “Macular degeneration is the most common and maybe the most complex choroidal retinal degeneration. It started to be understood in the 1960s, but it’s not that long ago that the sequence of the development of drusen and atrophy has been understood, in part,” Eric J. Sigler, MD, a retinal specialist, said here at SECO.
He discussed this group of disorders that have genetic and environmental defects in the retinal pigment epithelium, retina or choroidal function.
“The key take-home is that the visual sequelae are due to atrophy, and the cell loss is really not treatable at this point, so that’s one of the places that is frustrating to all of us,” Sigler continued.
“One of my professors used to say ‘disease is a great educator.’”
He explained that choroidal neovascularization occurs when there is a lack of balance in the body between things that are helpful and harmful.
“We want to find out more about the ontogenetic factors without damaging things that are necessary for stabilizing healthy cells,” he said.
Risk factors for age-related macular degeneration include: light iris color, European descent, age, “and smoking is by far the biggest thing I see that’s a variable between those that have advanced and those who have mild disease,” he added. “Smokers often don’t respond as well to treatment.”
In macular degeneration, the role of blood flow and VEGF is still not completely understood, he said.
When imaging patients, Sigler evaluates early drusen with optical coherence tomography and autofluorescence.
“Fluorescein angiography is something I will do when I think there’s the possibility of choroidal neovascularization or a retinal vascular problem,” he said. “It’s helpful in diagnosing blood flow and seeing some things that we can’t see in other ways.”
For example, in the case of a patient with unexplained vision loss where a macular problem is expected, he would use fluorescein angiography.
Fluorescein is not highly protein bound, so leakage and breakdown of blood-retina barriers can be observed. It will remain a helpful imaging tool, he said.
Indocyanine green angiography is important in patients with no obvious cause for vision loss when AMD or choroidal vascularization is suspected, Sigler said.
OCT angiography and Doppler OCT will probably become more important in the future, he said.
“They haven’t gained a lot of popularity, as they are not being used as a management tool, yet,” he said.
‘We are actually able to show that some patients who have choroidal neovascularization actually have a retinal blood vessel that is communicating with the choroidal neovascularization,” he added.
Many practitioners are interested in figuring out how OCT angiography can be used in this situation, but it does not show leakage, so we still use fluorescein angiography, he said.
“If we can identify high risk anatomy prior to the development of exudation and decreased vision, we can start preventing vision loss,” Sigler said. “Currently we are treating once patients are symptomatic.”
Choroidal thickness is an anatomic underpinning of risk for problems with macular degeneration, he said. – by Abigail Sutton
Reference:
Sigler E. Retina roundup. Presented at: SECO; March 1 - 5, 2017; Atlanta.
Disclosure: Sigler reported no relevant financial disclosures.