You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: A Review on the Extraction of Quantitative Retinal Microvascular Image Feature 
Chapter Title:  Retinal Vein Occlusion (RVO). 
1. Abstract of Cited Paper (BIB001):  Retinal vein occlusion (RVO) is a disease that is often associated with a variety of systemic disorders including arterial hypertension, diabetes mellitus, dyslipidemia and systemic vasculitis. There are various types of RVO, categorized on the basis of the site of occlusion and on the type of consequent vascular damage. Central retinal vein occlusion (CRVO) is the most clinically relevant type of RVO. In addition to well-known classical risk factors, new thrombophilic factors have been investigated in patients with RVO. Data concerning a number of the parameters remain contradictory; yet, hyperhomocysteinemia and vitamins involved in methionine metabolism appear to play a significant role in the pathogenesis of this disease. Alterations in the fibrinolysis pathway (elevated levels of PAI-1 and Lipoprotein (a)), together with haemorheologic modifications have been recently consistently associated with the disease. Medical treatment includes identification and correction of vascular risk factors. In addition, LMWHs appear to be the best therapeutic approach even if based on a limited number of trials, conducted on a limited number of patients. No data are available on the possible role of antithrombotic strategies in the long-term prevention of recurrent RVO or vascular events.

Literature Review:
Retinal Vein Occlusion (RVO) disorder is commonly associated with various underlying systemic disorders including arterial hypertension, diabetes mellitus, dyslipidemia, and systemic vasculitis. RVO may be found in varying blood vessel caliber. This includes central retinal vein occlusion (CRVO); media such as hemicentral retinal vein occlusion and small-caliber veins such as branch retinal vein occlusion (BRVO) BIB002 . Retinal vein occlusion can be divided into central and branch. The branch retinal vein occlusion can happen at the various tributary levels, especially the first and second tributaries. However, prior to a full-blown vein occlusion, a temporary phase known as impending retinal vein occlusion may occur. In this phase, the affected veins will become more engorged, dilated, and tortuous, and the course and tributary angle of the affected veins will alter with this pathological process BIB001 . These angular changes can be further studied to determine its significance in the prediction and assessment of disease progression.