located approximately 15 degrees nasal to the center of the retina and should appear to be yellowish orange (Figure 2FIGURE 2Normal Retina.). The optic cup is a pale central depression in the optic disk. The axons of the retinal ganglion cells exit the retina at the optic disk to form the optic nerve. In the retinal vasculature, veins are thicker and darker than arteries. The fovea is the area responsible for the highest visual acuity. It is temporal and slightly inferior to the optic disk and is surrounded by a more darkly pigmented region called the macula.
The cup-to-disk ratio, or the ratio of the diameter of the optic cup to the diameter of the optic disk, is normally 0.3. A high