On a topography map, a cone streak is described as occurring in which direction?

On a topography map, a cone streak is described as occurring in which direction?

• A. Nasal
• B. Temporal
• C. Superior
• D. Inferior

Answer: (A)

On topography maps, directions are labeled relative to the patient: nasal means toward the nose, temporal toward the temple, superior toward the top of the head, and inferior toward the chin. A cone streak describes where the region of greatest steepness or thinning extends on the map. In keratoconus patterns, the cone apex is commonly located in the inferior-nasal quadrant of the cornea, so the streak of steepening often runs toward the nasal side. That nasal orientation is why the description uses nasal. The other directions would imply the streak points toward the temple (temporal), the forehead (superior), or the chin (inferior), which is not the typical orientation for this feature.

On topography maps, directions are labeled relative to the patient: nasal means toward the nose, temporal toward the temple, superior toward the top of the head, and inferior toward the chin. A cone streak describes where the region of greatest steepness or thinning extends on the map. In keratoconus patterns, the cone apex is commonly located in the inferior-nasal quadrant of the cornea, so the streak of steepening often runs toward the nasal side. That nasal orientation is why the description uses nasal. The other directions would imply the streak points toward the temple (temporal), the forehead (superior), or the chin (inferior), which is not the typical orientation for this feature.