The eye is the window to the soul, and 90% of human information is obtained by vision. The only living blood vessel in the whole body that is visible is the fundus of the eye. An ophthalmologist uses a fundoscope to look at the fundus through the pupil. The normal pupil size is only 3mm, and the range of what can be seen is very small, depending on the experience of the doctor. Dilating eye drops (as long as the IOP is normal) can dilate the pupil and widen the scope of fundus observation. However, the patient can only learn about the condition of his or her fundus from the doctor’s description. If a fundus camera is used to take pictures of the fundus, the pictures can be printed out at the same time so that we can see the full picture of our own fundus. The fundus has very important structures, including the optic nerve, retina, retinal arterioles and vessels, and the macula (the center of vision). Fundus images are only flat images and have limitations. We can also do fundus fluorescence angiography, which is done by injecting fluorescein through the elbow vein while taking continuous pictures. It can clearly show the fine structure of microcirculation down to the capillary level, and obtain dynamic images at different times of taking pictures, and complete systematic expression of normal or abnormal state of circulation, as well as hemorrhage, exudation, fluorescein leakage, and capillary non-perfused areas. From fundus images we can diagnose various ocular diseases as well as internal diseases and diseases of the brain system. For example, optic neuropathy, retinopathy, retinal vasculopathy, macular degeneration, hypertensive arteriosclerosis, diabetic retinopathy, nephropathy, hematologic disease, cranio-cerebral disease, etc. The image above shows a normal fundus and a fluoroscopic image.