OCT Angiography Study of the Macula in Patients with Diabetic Macular Edema Treated with Intravitreal Aflibercept

Review on Recent Trials Evaluating the Effect of Intravitreal Injections of Anti-VEGF Agents on the Macular Perfusion of Diabetic Patients with Diabetic Macular Edema

“…In a prospective study of 20 eyes by Dastiridou et al . that evaluated the FAZ and vascular density following 3 aflibercept injections for treatment naïve patients with DME using swept source OCTA, there was a statistically significant decrease in the FAZ size in the deep capillary plexus but not in the superficial capillary plexus following injections with a high intergrader and intra-grader agreement for manual FAZ measurements [ 50 ]. Vascular density of the central area showed an 8% decrease following the injections, which was also statistically significant.…”

“…This probably reflects the current uncertainty surrounding the effect of these agents on the macular perfusion of diabetics, which prompted many researchers to attempt to resolve this uncertainty using the new and promising OCTA technology considering its perceived advantages in imaging the retinal microvasculature over conventional FA due to its ability to image capillary details, including the deep capillary plexus, in higher resolution without obscuration by dye leakage which allows better delineation and quantification of capillary non-perfusion areas [ 58 , 59 ]. Regarding studies done using OCTA, 3 studies showed stable macular perfusion following injections [ 47 , 49 , 53 ], 6 studies showed worsening macular perfusion following injections [ 15 , 31 , 46 , 51 , 52 , 54 ], and 2 studies showed conflicting results [ 48 , 50 ]. This may have been due to differences in study design, patient inclusion criteria, or method of analysis.…”

“…Indeed, even in the single patient, it is apparent that some retinal areas become better perfused while others get worse on OCTA following the injections suggesting that several competing factors are in play [ 60 ]. Factors resulting in improvement of retinal perfusion following anti-VEGF injections include reversal of VEGF-induced leukostasis, which results in increased capillary occlusion [ 25 ], restoration of the normal retinal architecture [ 50 ], and inhibition of endothelial cell hypertrophy that is induced by local VEGF-A production and leads to progressive capillary lumen narrowing [ 61 ]. Factors explaining retinal perfusion worsening following anti-VEGF inhibition include induction of vasoconstriction of retinal blood vessels which was seen following bevacizumab and ranibizumab injections for DME and could be due to inhibition of nitric oxide which is known to occur with VEGF inhibition and also results in systemic hypertension in case of systemic VEGF inhibition [ 62 , 63 ].…”

Clinical effect of conbercept on improving diabetic macular ischemia by OCT angiography

“…Other limitations in our study mainly include the small sample size and the short study period. Indeed, a part of studies used OCTA observing changes in macular perfusion and found there is no improvement in FAZ and vessel density after anti-VEGF [34][35][36][37]. The effects of anti-VEGF therapy on DMI need a larger sample size and a longer observation period to determine how anti-VEGF plays a role in improving macular ischemia and retinal ischemia and realizing reperfusion in nonperfusion areas.…”

Vessel Density Changes on Optical Coherence Tomography Angiography after Vascular Endothelial Growth Factor Inhibitor Treatment for Diabetic Macular Edema

“…In the assessment of diabetic retinopathy (DR) and DME, OCTA attempts to provide various quantitative parameters including vessel density and foveal avascular zone (FAZ) area. 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 Of interest in this study is vessel density on OCTA, which is a quantification of the number of vessels in a region of interest. 23 Many studies have reported decreased vessel density in the SCP and DCP in eyes with DR and DME compared with normal controls.…”