Effect of Ranibizumab Versus Bevacizumab on the Macular Perfusion in Diabetic Macular Edema
Status:
Not yet recruiting
Trial end date:
2022-11-01
Target enrollment:
Participant gender:
Summary
The Early Treatment Diabetic Retinopathy Study (ETDRS) group founded guidelines for treating
patients with clinically significant diabetic macular edema (DME) with focal/grid macular
laser photocoagulation. Since then, macular laser, and steroids, were the main therapies for
the treatment of DME until anti-vascular endothelial growth factors (anti-VEGF) drugs were
developed after a growing body of scientific evidence implicated VEGF in the pathophysiologic
process of DME.
Anti-VEGF drugs have been implicated in the treatment of DME. VEGF has been shown to play an
important role in the occurrence of increased vascular permeability in DME. VEGF levels are
significantly higher in patients with DME and extensive leakage than in patients with minimal
leakage.
Many studies such as Diabetic Retinopathy Clinical Research [DRCR] Network studies, RESTORE
Study, RISE and RIDE Research Group, and The BOLT Study have supported the use of anti-VEGF
agents in the treatment of DME with better visual outcomes using anti-VEGF injections alone
or in combination with other treatments.
Several ocular complications of intravitreal anti-VEGF injections have been reported
including endophthalmitis, cataract, and retinal detachment. The different effects on macular
perfusion between different anti-VEGFs have yet to be fully concluded with mixed conclusions
that it increases or decreases or has no effect on perfusion of the macula in response to
Anti-VEGF treatment. In many of these studies, however, patients with more ischemic retinas
were not included. Retinal ischemia is a vital factor determining the diabetic retinopathy
progression and prognosis.
Optical coherence tomography angiography (OCTA) detects blood flow by analyzing signal
decorrelation between two sequential OCT cross-sectional scans at the same location. As it
detects the movements of red blood corpuscles within the vessels, compared to the stationary
retinal surroundings, which will result in signal disparity and imaging The split-spectrum
amplitude-decorrelation angiography (SSADA) algorithm improves the signal to noise ratio.
OCTA is considered a reliable tool in the detection and quantification of macular ischemia in
diabetics.
In this study, the investigators aim to compare the effect of repeated intravitreal
injections of ranibizumab and bevacizumab on the perfusion of different capillary layers in
the macula of diabetic patients using OCTA.