Type‐Size Variability for Near‐Point Acuity Tests

We measured the sizes of the test forms (letters, digits, and symbols) on 19 different near‐point acuity cards. The results are all expressed in the M notation (1 mm of letter height equals 0.7 M) and are tabled according to the acuity specification system used by the manufacturers‐such as, the point‐type system, Jaeger notation, equivalent 20‐ft Snellen notation, and so on. Our results demonstrate that manufacturer's specifications on near‐point acuity cards cannot be used to determine the sizes of test letters. The M system has sufficient advantages over other systems to warrant its universal use for specifying near‐point visual acuity.