Fig. 17. Tilted disc with vessel trunk penetrating the lamina cribrosa in the upper nasal region and a sloped temporal margin. Moreover, the disc is large, and a large physiologic cup would be expected. Some thinning of tissue in the sloped inferior sector may be suspected, but the neuroretinal rim at the superior pole of the disc is distinctly thinner than the rim in the nasal and other sectors (violating the inferior, superior, nasal, temporal [ISNT] rule). Finally, the white base of the cup, contrasted with the adjacent pinker tissue of the neuroretinal rim, is taller than it is wide; this is virtually never seen in normal discs.