The fundus can be examined by direct fundoscopy, slit lamp with anterior mirror, indirect fundoscopy and other equipment to directly observe the fundus of the eye, such as the optic papilla, blood vessels, macula, peripheral retina and other important structures. Direct fundus observation mainly looks at the shape, size, color and clarity of the optic nerve papilla, observe the retinal artery and central retinal vein, pay attention to their thickness and travel, pay close attention to the degree of reflection and crossover of the artery and vein in the fundus, the normal ratio of artery to vein is 2:3, observe the macula, pay attention to the form of the macula whether there is edema, hemorrhage and exudation whether there is neovascularization; observe the peripheral retina whether there is hemorrhage, hemorrhage and neovascularization. Observe the peripheral retina for hemorrhage, degeneration, fissure, retinal detachment and other lesions. The fundus can be photographed, usually under the small pupil and under the scattered eye. Optical coherence tomography (OCT), fluorescein angiography, indocyanine green angiography, and OCT of the optic papilla can also be done. In addition, retinal current mapping is a test to assess the electrophysiological response of the retina and is needed to identify certain diseases. In summary, fundus examinations can be performed either directly by the physician with a detector, or with equipment such as fundus photography, OCT, fundus angiography, and retinal current diagram.