• Imaging Nonperfusion in Patients With DME: Comparing Techniques

    By Lynda Seminara
    Selected By: Stephen D. McLeod, MD

    Journal Highlights

    Ophthalmology, December 2019

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    Couturier et al. compared retinal non­perfusion observations for two imaging modalities after anti-VEGF treatment of diabetic macular edema (DME). They found that swept-source widefield optical coherence tomography angi­ography (SS-WF OCTA) performed better than ultra-widefield fluorescein angiography (UWF FA) in detecting nonperfusion. However, after three treatment sessions, neither modality demonstrated reperfusion of arterioles or venules in areas of nonperfusion, despite improvement in the severity of diabetic retinopathy (DR).

    This study was performed in nine patients (10 eyes) who had prolifera­tive or severe nonproliferative DR. All received three intravitreal anti-VEGF injections for their DME, and all eyes were imaged with UWF color fundus photographs, UWF FA, and SS-WF OCTA. Imaging took place at baseline and one month after the third injection. The images were aligned and then divided into 16 identical boxes for analysis by two masked retina special­ists. Main outcome measures included discrepancies in detection of nonperfu­sion between the two imaging modali­ties; assessment of DR severity by UWF fundus photographs; and changes in each area of nonperfusion between baseline and follow-up. (For the latter, this included the number of 1) boxes per eye with at least one area of non­perfusion, 2) arterioles or venules that disappeared or reappeared, and 3) areas of nonperfusion in which capillaries disappeared or reappeared.)

    Results showed that DR severity improved by at least one stage in eight of the 10 eyes. Evidence of this included a decrease in the mean number of mi­croaneurysms and retinal hemorrhages on UWF photography at follow-up (40 ± 28 vs. 121 ± 57 at baseline; p = .0020) and by regression of fundus neovas­cularization if it had been present. All areas of nonperfusion identified by UWF FA also were observed with SS-WF OCTA, but the latter detected additional areas at baseline in 29% of boxes. Neither modality showed reperfusion of arterioles or venules at follow-up, even when a reduction in dark areas was apparent by UWF FA. Retinal capillaries were visible only with SS-WF OCTA.

    The authors concluded that the unchanged number of areas of non­perfusion implies that neovascular complications may persist even if DR improves. Absence of reperfusion following anti-VEGF therapy highlights the risk of visual loss in patients who miss scheduled treatments.

    The original article can be found here.