Documentation of the Optic Nerve evaluation, nerve head morphology, subjective evaluation of the health of the nerve as well as the presence of neovascularization at or near the optic nerve.

What does the “Disk Type” field mean?

Disk Type allows the provider to document the morphology of the normal optic nerve based on Elschnig’s classification system.

I: Funnel-shaped: small cup with shallow depth

“A small, funnel-shaped excava­tion. Its bottom is pointed or somewhat rounded and does not as a rule reach beyond the plane of the inner opening of the scleral canal. It lies centrally or slightly temporally. Its walls are steep on all sides, though less steep on the temporal side. The vessels are usually in the nasal wall. The artery bifur­cates on the surface of the disk, while the vein branches in the bottom of the cup. The nerve is rich in connective tissue, and the surface of the disk projects toward the vitre­ous.”

II: Cylinder-shaped: defined cup border, no gradual sloping, variable in C/D size and depth

“A temporal, almost cylindric excavation. The steep nasal wall almost coin­cides with the center of the disk, but the temporal wall may be somewhat flatter. The cup may be partly filled with connective tis­ sue, so that only a small excavation remains. The course of the vessels and the shape of the canal are similar to those in Type I. The markings of the lamina cribrosa are usually visible on the floor of the excavation.”

III: Saucer-shaped: temporal border is not sharp, gradual sloping, variable in C/D size and shape

“A symmetrical, central trough-shaped excavation, and its walls pass gradually into the level of the retina. The vessels enter more nasally. The central ar­tery and vein bifurcate within the cup. The individual vessels emerge either at the ante­rior border of the excavation or from within the nasal nerve fiber wall. The markings of the lamina cribrosa are distinct. Large flat excavations of this type may cover two thirds the width of the disk. The cup may be quite deep.

IV: Hook-shaped: temporal cup border is not sharp, gradual sloping, nasal hook, oblique insertion or tilted disk

“This cup lies either centrally or to the temporal side. The connective tis­sue is well developed on the nasal side, and the cup may have a steep wall. The temporal wall is indistinct and slopes gradually up to the level of the retina. The cup reaches the temporal edge of the disk but never has a steep wall. A Type IV cup looks like a Type II or Type III cup in which the temporal wall is bent outward.”

V: Bean pot: large, deep cup with visible lamina cribrosa, vessels plunge over rolled rim tissue

“An atypical excavation (which) occurs in developmental anomalies of the optic nerve entrance, such as coloboma of the choroid at the border of the op­tic nerve, reversed vessel distribution and conus below. The excavation is usually di­rected toward the greatest width of the co­nus. The high side of the nerve fibers seems to overhang the excavation, while the oppo­site side slopes gradually to the level of the retina.”

quotation reference: http://goo.gl/1WFxY9 “Qualitative Parameters of the Normal Optic Nerve Head” by Gerald L. Portney, MD, Department of Ophthalmology, University of California – Davis.