OCT angiography can identify neovascularization in diabetic retinopathy
OCT angiography can provide a noninvasive option for imaging neovascular complexes, intraretinal microvascular abnormalities and retinal nonperfusion areas in patients with diabetic retinopathy.
“OCTA, despite some current technical limitations, is becoming important in [proliferative diabetic retinopathy (PDR)] evaluation and gaining further relevance in this area, becoming a quick and inexpensive tool in diagnosing and guiding treatment,” Sara Vaz-Pereira, MD, from the Hospital de Santa Maria in Lisbon, Portugal, and colleagues wrote.
Vaz-Pereira and colleagues enrolled 21 patients with diabetic retinopathy, among whom 35 eyes had neovascular complexes. Specifically, there were 12 cases of neovascularization of the disc (NVD) and 23 cases in which the neovascularization was elsewhere (NVE).
The researchers observed flow signal in 89% of overall cases, including all of the NVE cases and eight patients with NVDs. En face projections showed the active NVCs as vascular loops or filamentous irregular new vessels. Exuberant vascular proliferation was found in 13 cases of NVC. Twenty patients with NVEs had adjacent retinal nonperfusion areas, identified as “retinal areas of absent flow signal or sparse capillary density.”
Further observation showed no significant relation between retinal nonperfusion areas and intraretinal microvascular abnormalities, between the morphologic classification and NVE type or posterior hyaloid state, or posterior shadowing and cases of NVD.
“The eye tracking software on most OCTA devices makes it possible to track the vascular lesions in follow-up observation, as shown in the case presentations,” the researchers wrote. “These capabilities alone or in combination with other image techniques can be very useful in PDR screening and monitoring, or to guide surgical or clinical treatments.”
Perspective
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Forty years ago, the landmark study, Early Treatment Diabetic Retinopathy Study (ETDRS), started to provide industry-changing clinical insight into diabetic retinopathy. ETDRS set the standard of diabetic retinopathy management at the time.
But 40 years is ancient in the continually changing medical world. Anti-VEGF agents have mostly taken over the role of focal and grid laser in the ETDRS era. The term, “clinically significant macular edema,” has been replaced by center-involved diabetic macular edema for treatment decisions.
The last of the ETDRS era is fluorescein angiography (FA). OCTA offers a significant advantage over traditional FA. It is patient- and doctor-friendly, allowing instant and frequent usage. Its 3D rendering allows differentiation from confusing lesions, such as intraretinal microvascular abnormalities. It also allows a better understanding of different types of neovascular complexes.
OCTA has its shortcomings. Its range is limited to a small area of the fundus at this moment. It is not capable of showing leakage, which may be critical in diagnosing certain ocular diseases. But it is evident that we are in a pivotal phase and witnessing OCTA taking over the traditional role of FA. We must continue educating ourselves about the new diagnostic technology with good quality material like the present manuscript.
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