The S-22 loose prism set is designed to aid in the measurement of phoria deviations. High grade Lucite insures a precise surface quality. Includes the following diopters:
Red lens, 1/2, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50