![]() ![]() The dye is metabolized by both hepatic and renal pathways and is excreted in the urine within 24-36 hours. Approximately 80% of fluorescein dye remains in the intravascular compartment binding to albumin, while remaining is free. Sodium fluorescein is orange in color, it’s molecular weight of 376. The sodium fluorescein molecule has fluorescence as part of it characters which means-its ability to absorb a photon of light of shorter wavelength and emit a photon of light of a longer wavelength. The development of FA increased the understanding of retinal and choroidal pathology and has become the standard both in the literature and in clinical practice to diagnose and guide the treatment of the most common retinal diseases encountered in ophthalmology. It’s main function is control and prevents entry of certain substance to the tissue of the retina.įigure 5 Comparison between retinal and choroidal capillaries.Īny disturbance in this tissue and their vasculature will lead to pathological change and functional disturbance of the vision. These barriers called the blood-retina barrier (BRB). Inner retinal barrier: consists of non-fenestrated capillaries of retinal circulation ( Figure 5). Outer retinal barrier: consists of tight junctions between the retinal pigment epithelium (RPE) 2. 2 The degree of pigmentation and the pathologic changes in this pigmented layer markedly influence the choroidal angiographic appearance there is two barriers in the retina: 1. The choroid and it’s vasculature lie posterior to the RPE, the fluorescein angiographic patterns of the posterior uvea are, therefore, always partially obscured by the RPE. The ocular fundus has two separate vascular systems-retinal and choroidal-separated by a specialized pigmented monolayer the retinal pigment epithelium (RPE) ( Figure 3) ( Figure 4). The choroid nourishes the outer retina and a portion of the optic nerve. ![]()
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