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AMA Manual of Style (10th ed.) : A Guide for Authors and Editors

AMA Manual of Style Committee

Publisher:
Oxford University Press
Print Publication Date:
Mar 2007
Print ISBN-13:
9780195176339
Published to AMA Manual of Style:
Apr 2009
DOI:
10.1093/jama/9780195176339.001.0001
© American Medical Association
Contents

Visual Acuity

Chapter:
Units of Measure
Author(s):

Phil B. Fontanarosa,

Stacy Christiansen

18.5.4 Visual Acuity

Visual acuity should be reported on the basis of how the measurement was determined. For example, using the Snellen fraction with English units, 20/20 or 20/100 indicates that the person being evaluated can see at 20 ft what a person with “normal visual acuity” can see at 20 ft or at 100 ft, respectively. The equivalent metric measurements for visual acuity are 6/6 and 6/30, respectively. (See 15.13, Nomenclature, Ophthalmology Terms.)