Maddox rod test is used primarily to:

Maddox rod test is used primarily to:

• A. To measure corneal curvature.
• B. To assess stereoacuity.
• C. To evaluate convergence.
• D. To reveal latent misalignment by converting a point light to a line, used to quantify phorias and sometimes torsion.

Answer: (D)

The Maddox rod is a dissociating test that reveals latent ocular misalignment by turning a point light into a line for the eye wearing the rod, which lets you quantify phorias and, with rotation, torsion. When one eye sees a line and the other eye sees a point, any misalignment disrupts fusion and shows up as a relative offset between the line and the point. Measuring that offset gives the magnitude and direction of the latent misalignment in prism diopters, and rotating the rod can reveal torsional components. This is why it’s primarily used to detect and quantify phorias (and sometimes torsion). It doesn’t measure corneal curvature (keratometry), nor is it a direct test of stereoacuity, and while it relates to vergence demands, its main purpose isn’t assessing convergence ranges.

The Maddox rod is a dissociating test that reveals latent ocular misalignment by turning a point light into a line for the eye wearing the rod, which lets you quantify phorias and, with rotation, torsion. When one eye sees a line and the other eye sees a point, any misalignment disrupts fusion and shows up as a relative offset between the line and the point. Measuring that offset gives the magnitude and direction of the latent misalignment in prism diopters, and rotating the rod can reveal torsional components. This is why it’s primarily used to detect and quantify phorias (and sometimes torsion). It doesn’t measure corneal curvature (keratometry), nor is it a direct test of stereoacuity, and while it relates to vergence demands, its main purpose isn’t assessing convergence ranges.