الفهرس 
Aim of The WorkOnly 14 pages are availabe for public view
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Abstract
Diabetic retinopathy is a widely prevalent sequel of diabetes mellitus with multiple risk factors and predisposing conditions, it is a retinal vascular disorder characterized by many pathological changes and visible gross findings in the retina of the diabetic patients.
Diabetic macular edema (DME) is the swelling of the retina resulting from the exudation and accumulation of extracellular fluid and proteins in the macula.
In DME, the development of retinal ischemia leads to an increase in production of vascular endothelial growth factor (VEGF), which increases vascular permeability by affecting endothelial tight junction proteins
Histopathologic studies also have implicated choroidal dysfunction in diabetics. These changes include loss of the choriocapillaris, increased tortuosity, narrowing and dilation of vessels, and sinus-like structure formation between choroidal lobules.
The identification of VEGF as an important pathophysiologic mediator of DME suggested that anti-VEGF therapy delivered to the eye might lead to improved visual and anatomic outcomes in this disease, thus anti-VEGF therapy has become the preferred treatment option for the management of DME in many patients
Ranibizumab (Lucentis®, Genentech/Roche) is a fully humanized monoclonal anti-VEGF-A fab fragment developed specifically for ophthalmic applications. Ranibizumab was designed to blind all biologically active forms of VEGF.
As Ranibizumab exerts an anti VEGF-A effect on the retinal blood vessels it also does the same for choroidal vasculature, the anti VEGF effect in the choroidal circulation is similar to retina in many ways but it hasn’t been fully studied as there are only few clinical studies on choroidal changes in diabetes because of the difficulty of imaging the choroid in vivo.