I introduce the fundus camera and discuss the light ray paths for the illumination light rays and the reflected light rays. The fundus camera can obtain images of the retina, optic nerve head, macula, retinal blood vessels, choroid, and the vitreous. The oxygen source and the functioning of the outer retina, Layers 1–5, is totally dependent on its supply from the choroidal vasculature. Harold Ridley is credited with the prescient invention of Electronic Ophthalmoscopy. This is another example of the transfer of optical technology to a clinical medical device. I describe the invention and clinical development of fluorescein angiography and indocyanine green angiography to view the vascular system in the retina and in the choroid. In summary, the human retina is supplied with oxygen from the retinal vascular system and also from the choroidal vascular system and both are necessary for the normal oxygenation of the retina. I describe my research on the fractal analysis of the vascular tree in the human retina.