One of the amazing things about the eye is that it’s designed to gather light, but it is not where we actually see. Sight actually takes place in the visual cortex, which is located in the back of the brain. Many remember being taught in school that the eye transmits the images seen to the brain upside down and the brain in turn flips the image upright. This is indeed the case! The optic nerve is the “wire” between the eyes and the visual center of the brain. Maintaining the integrity and health of the optic nerve is critical for eyesight.
On the right, you will see the picture of what a healthy optic nerve looks like to our doctors when they evaluate your eyes. You will notice a central cup, which is the dead part of the optic nerve. The rim tissue around the outer edges is the healthy, living part of the optic nerve. As the central cup (dead area) grows, the living area shrinks. If the central cup ever completely reaches the outer rim of the nerve, we have reached blindness. The average cup typically is between a .2 (central 20%) to a .4 (central 40%).