Two smaller groups 5M to 1.6M for repetitive testing (20/25, 6/7.5 to 20/8, 6/2.4 equiv.).
Can be wall-mounted.
PV numbers are an alternative vision test to Sloan, Snellen, Patti Pics, Landolt C, and Tumbling E tests. PV Numbers are designed for vision testing in several different languages and for several types of patients. The PV Number test can be used for languages across the globe. Also, PV Numbers are useful for mute patients and for children who may be preliterate but may know their numbers.