Type‐Size Variability for Near‐Point Acuity Tests
作者:
RANDALL JOSE,
RAY ATCHERSON,
期刊:
American Journal of Optometry and Physiological Optics
(OVID Available online 1977)
卷期:
Volume 54,
issue 9
页码: 627-638
ISSN:0093-7002
年代: 1977
出版商: OVID
关键词: visual acuity;near vision;acuity test cards;optotype size;acuity specification;M system;standardization
数据来源: OVID
摘要:
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.
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