Study of Optic Disc and Macular Vascularity in Central Retinal Vein Occlusion Using Optical Coherence Tomography Angiography

Background Retinal vein occlusion (RVO) is a sight threatening disease. It is the second most common vascular retinal disease after diabetic retinopathy. Central retinal vein occlusion (CRVO) is considered as the most dreadful form, with prevalence of nearly 1 in 1000 in the population aged ≥30 years. Aim of the Work To quantify changes in optic disc and macular vasculature in patients with CRVO using optical coherence tomography angiography. Patients and Methods In our study, we included 20 eyes of twenty patients with treatment naïve cases of CRVO. These cases were selected from the outpatient clinic at Ain shams University Hospital between January 2020 and October 2021. Included subjects were patients diagnosed with CRVO, who received no previous treatment neither by injection nor by laser. Only patients with media opacity that are dense enough to impede sufficient image quality for reliable interpretation were excluded. Results Our study was able to prove the agreement between the quantitative vessel density (VD) measurement in the macula and the current fundus fluorescein angiography (FFA) based assessment of macular ischemia. We were able to confirm a deep component to the pathological process in CRVO as proposed by the current literature and be able to assess it simultaneously in relation to the superficial microcirculation using optical coherence tomography angiography (OCTA) and FFA. We found the optic disc VD parameters to be a significant indicator of global retina perfusion which could be of value in assessment and follow up of patients especially in the presence of confounding factors for macular VD measurement as extensive edema. We found significant correlation between FAZ size and measured macular vessel density indicating congruity of the two ischemic parameters. Conclusion OCTA is a new modality for retinal imaging, providing a noninvasive alternative for the gold standard FFA. It visualizes microvascular changes in cases of vascular diseases at least with the same sensitivity as FFA. It has the definite advantage of being easily repeated in case of poor quality and patients who needs recurrent follow up imaging. It can be also used in patients who don’t qualify for or with contraindications to FFA. However, OCTA is liable to inaccuracy due to inherent disadvantages as segmentation and projection artifacts.