Fig. 1.

(Left) Volume scan (C-Scan) of the optic nerve head (ONH). (Right) The volume scan consists of slices (B-scans), where each column is an axial depth scan (A-Scan). The ONH typically has a cup in its center (1). The blue line marks the inner limiting membrane (ILM) separating the vitreous body (2) from retinal tissue (3). The magenta line represents the Bruch’s membrane (BM). Note how the blue line failed to correctly detect the ILM, and misses the vessel at the left top, as well as the deep cuping.