To diagnose diabetic retinopathy, an ophthalmologist uses an ophthalmoscopic examination or fluorescein angiography. During an ophthalmoscopic examination, the ophthalmologist dilates the patient’s eyes with a mydriatic drug, such as atropine. This dilation permits viewing of the retina, retinal blood vessels, optic disc, macula, and other structures.The ophthalmologist uses fluorescein angiography to evaluate leaking or occluded retinal vessels. In this outpatient procedure, fluorescein dye is injected into an arm vein. Then the dye travels through the blood to different parts of the body, including the retinal capillaries. By using fluorescein dye and a fundus camera with filters, the ophthalmologist can better see the retinal blood vessels and determine if the patient has retinopathy and, if so, to what extent.