Evaluating diplopia with the Maddox rod, Risley's prism, and red glass

1. Using Maddox rod, Risley's prism, and red glass techniques can provide the doctor with the information needed to diagnose the reasons for diplopia. 2. The Maddox rod and Risley's prism help to determine misalignment in primary position. The red glass test provides valuable information on the type of muscle problems in all other fields of gaze. 3. Both tests should be used for any patient complaining about recent symptoms of diplopia.