are optic nerve and optic disc the same thing
Dr. Jeff Henderer: There is a very specific way that the nerve fibers from the retina feed into the optic nerve. The fibers from the temporal retina enter from the north and south poles of the nerve. The temporal side of the nerve serves the macula (where we do fine vision), and the nasal nerve serves the nasal retina. In fact, the changes that you see in glaucoma are pretty specific to glaucoma. Optic nerve compression generally shows up as pallor of the nerve, not cupping. The same can be said of a “stroke” of the nerve. When the blood supply is cut off, the changes are not generally the same as you see in glaucoma. Nerve elevation due to disc drusen is usually apparent in childhood as a “full” optic nerve that simulates papilledema (figure 11A). As the person ages and this pseudopapilledema changes, the optic nerve takes on a scalloped appearance at the nasal disc margin (figure 11B). Diseases of the optic nerve usually result in characteristic features, including reduced visual acuity and color vision, a relative afferent pupillary defect (RAPD), visual field defects and changes in the optic disc appearance (e.g., swelling, pallor or cupping). Optic Disc & Optic Nerve. The optic disc is a round area in the back of the eye where retinal nerve fibers collect to form the optic nerve. The optic disc is sometimes called the optic nerve head because it is the head of the optic nerve as it enters the eye from the brain. It is located slightly to the nasal side of the globe. The optic disc is known as the blind spot because it contains no photoreceptors. The appearance of the optic nerve and retina can help determine the presence of papilledema. Papilledema is usually bilateral and symmetric (figure 13). The optic nerve head appears hyperemic. Paton’s lines (circumferential retinal folds surrounding the disc) are often present. One key warning sign: optic atrophy. This represents irreversible damage to the optic nerve. Atrophy is diagnosed based on the color and structure of the optic nerve, nerve fiber layer and retinal blood vessels. Typically, the optic nerve exits the sclera at a 90º angle. A tilted optic nerve occurs when the nerve exits the eye at an oblique angle. Tilted disc is usually a bilateral condition in which the superiortemporal disc is raised, simulating disc swelling, while the inferiornasal disc is flat or depressed (figure 9). The optic nerve head, or disc, is defined as the distal portion of the optic nerve extending from the myelinated portion of nerve that begins just behind the sclera, to the retinal surface. Typically, it is slightly oval with the vertical diameter being about 9% greater than the horizontal. Dr. Jeff Henderer: Sure. The optic nerve is the structure in the eye that contains a bundle of small nerve fibers wrapped into one large nerve fiber that takes the signal from the retina to the brain. It’s sort of like a fiber optic cable.
No, optic nerve and optic disc are not the same thing.