The Phoria Measure is a rotary monocular Maddox hand frame, used vertically or horizontally with either eye, incorporating a rotating 10D prism. Exophoria or esophoria show up in diopters when patient sees streak pass through spot of light. Red Maddox Rods are perpendicular to the handle. Therefore, when handle is vertical, Maddox rods are horizontal and the patient sees a vertical streak. When the handle is horizontal, Maddox rods are vertical and the patient sees a horizontal streak. A scale from 0 - 10 prism diopters indicates the measure of imbalance. The Phoria Measure is necessary equipment for aviation certification testing and a staple of the aviation medical examination. Supplied with soft case and instructions.