Maddox rod ridges orientation when measuring vertical deviations?

Maddox rod ridges orientation when measuring vertical deviations?

• A. Diagonally
• B. Horizontally
• C. Vertically
• D. No orientation matters

Answer: (C)

The Maddox rod turns a point light into a line image, and the line’s orientation is perpendicular to the ridges of the rod. To measure vertical deviations clearly, you want the line to lie horizontally so you can judge its vertical offset against the fixation point. That happens when the ridges are oriented vertically. So, for measuring vertical deviations, the ridges should be oriented vertically. If the ridges were oriented differently, the line would take a different direction and the vertical misalignment would be harder to read.

The Maddox rod turns a point light into a line image, and the line’s orientation is perpendicular to the ridges of the rod. To measure vertical deviations clearly, you want the line to lie horizontally so you can judge its vertical offset against the fixation point. That happens when the ridges are oriented vertically. So, for measuring vertical deviations, the ridges should be oriented vertically. If the ridges were oriented differently, the line would take a different direction and the vertical misalignment would be harder to read.