Visual Acuity - AMA Manual of Style

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Visual Acuity 

Units of Measure

Phil B. Fontanarosa

and Stacy Christiansen

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PRINTED FROM AMA MANUAL OF STYLE ONLINE ( © American Medical Association, 2009. All Rights Reserved. Under the terms of the license agreement, an individual user may print out a PDF of a single chapter of a title in AMA Manual of Style Online for personal use (for details see Privacy Policy). date: 24 November 2015

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 , Nomenclature, Ophthalmology Terms.)

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