Question

Identify the instrument

• A. Blade no. 15
• B. Blade no. 10
• C. Blade no. 11
• D. Blade no. 12

Answer 1

The Correct Option is C

Step 1: The pictured device is the Maddox rod, a handheld bank of red cylindrical lenses.
Step 2: When a patient views a spot light through it, the cylinders convert the spot into a perpendicular red streak, breaking fusion between the two eyes.
Step 3: By judging the position of the streak relative to the light (diplopic projection), the examiner quantifies horizontal or vertical, latent or manifest deviations at distance and near.
Step 4: Because the Maddox wing measures only near heterophoria and red glasses simply tint vision, the correct identification of this streak-producing instrument is the Maddox rod.
\[\boxed{\text{Maddox rod}}\]