Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Ophthalmology

Purpose: To demonstrate the characteristics of retinal vein occlusion (RVO) detected by optical coherence tomography angiography (OCTA) in comparison to the conventional fluorescein angiography. Design: Cross-sectional, observational study. Methods: A total of 34 eyes of 32 patients (with a known clinical diagnosis of RVO; any stage, any type), were recruited. All patients underwent standard ophthalmological examination together with multimodal imaging procedures including; color fundus photography, fluorescein angiography and optical coherence tomography angiography using the RTVue XR Avanti machine. All imaging procedures were performed on the same day or during the same week without in-between intraocular injections or laser treatment. Quantitative flow analysis of the SCP has been performed for selected 29 images of 29 eyes (15 with CRVO and 14 with BRVO) versus a single eye of a normal control. Results: Optical coherence tomography angiography can qualitatively demonstrate all the macular complications of RVO including; ischemia, capillary dilation, microaneurysms, collateral vessels, edema and intraretinal hemorrhages, with superiority to fluorescein angiography especially in the presence of retinal hemorrhages and retinal edema. OCTA with the help of the co-registered en face OCT images, can demonstrate laser scars, at the level of the choriocapillaris and can help in detecting disc edema. Statistical analysis of the incidence of the different pathological findings in RVO, has revealed more severe affection of the deep capillary plexus than the superficial one. Analysis of the grid-based vessel area density percentage of the SCP, has revealed that RVO is injurious to the retinal vasculature (the mean value of the vessel density of the RVO group was found to be 45.47 ± 5.06 % and that of the normal control was 48.18 ± 3.95 %, with P < 0.05), and the BRVO is more injurious to the retinal vasculature than the CRVO (the mean value of the BRVO group was found to be 44.77 ± 5.25 % and that of the CRVO group was 46.12 ± 4.78 %, with P < 0.05)

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