Optical coherence tomography angiography (OCTA) is a promising new approach for visualizing retinal vascular pathology in eyes with diabetic eye disease that can be expected to have even greater utility in the future pending further enhancements.
“Compared with fluorescein angiography, OCTA is a faster and noninvasive imaging technique performed without the need for injecting dye, and it allows for correlation of structure to vasculature,” said Nadia K Waheed, MD, MPH. “However, enhancements are needed to allow for better evaluation of blood flow and true widefield imaging.
Dr. Waheed is associate professor of ophthalmology, New England Eye Center, Tufts University Medical Center, Boston.
Discussing the use of OCTA for the evaluation of patients with diabetic eye disease, Dr. Waheed explained that the fully mature retinal circulation at the macula is probably comprised of four different plexuses that are typically subdivided as being superficial and deep based on their location relevant to the inner plexiform layer. Fluorescein angiography primarily images only the superficial retinal plexus, whereas the deep vasculature can also be visualized using OCTA.
“Because OCTA is a depth-resolved imaging technique, it has the advantage compared with fluorescein angiography of separating the superficial and the deep vasculature,” Dr. Waheed explained. “This feature has relevance in patients with diabetes because the deep vasculature tends to be affected earlier in patients who develop diabetic eye disease.”
In the few years since OCTA was introduced, it has shown to enable better visualization of capillary abnormalities in eyes with diabetic retinopathy, allowing the identification of changes in the deep plexus that are not evident on fluorescein angiography.
“Diabetic vasculopathy typically develops much sooner than diabetic retinopathy becomes clinically apparent,” Dr. Waheed said. “Using OCTA in patients with diabetes and clinical evidence of diabetic retinopathy, we found that they not only had changes in their retinal vasculature but also had a diabetic choroidopathy.”
The vascular abnormalities also can be mapped and quantified using OCTA. By doing so, researchers have described changes in the foveal avascular zone, perfusion, and arborization of the vascular network at the macula that are commensurate with the severity of diabetic retinopathy.
“In the future, commercially available OCTA systems will have software modules for monitoring patients over time based on quantification of these deteriorations,” Dr. Waheed added.