الفهرس 
Aim of the workOnly 14 pages are availabe for public view
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Abstract
Diabetes mellitus, a disease widespread across the world, is one of the main causes of blindness in developed countries. Microvascular and macrovascular circulatory impairment develops as a result of chronic hyperglycemia developing in diseases and has a negative impact on several organs. The retina, a tissue especially sensitive to hypoxia because of its rich blood circulation, is also negatively impacted by this process, resulting in DR involving a number of pathologic changes, such as retinal ischemia and oxidative stress related neovascularization in the eye and macular edema (Adem et al., 2011).
Diabetic retinopathy is one of the most significant complications of DM. DR is a major cause of vision loss in patients with diabetes (Ciulla et al., 2003). Therefore, within three to five years after the onset of type 1 diabetes and shortly after the diagnosis of type 2 diabetes, the diabetic patients are recommended to be screened for retinopathy with an initial dilated and comprehensive eye examination by an ophthalmologist regular (Zhu and Zou, 2012). The longer the duration of the diabetic patients, the higher the prevalence of DR (Ciulla et al., 2003). It occurs in90% of patients after 20–30 years from the disease diagnosis and its advanced form, proliferative diabetic retinopathy (PDR), affects over 60% of diabetic patients