Version 2.78

Descriptions

When discussing visual acuity, such as 20/40, the numerator is the testing distance. In the US, 20 is measured in feet. In the metric system, the testing distance is measured in meters. Normal visual acuity is commonly referred to as 20/20 vision and the metric equivalent is 6/6 vision.

The denominator is also a distance - the distance at which the size of the tested letter would subtend an arc of 5 minutes; what changes is the size of the letters and the distance at which the letters subtend that 5 minutes of angle. A letter of the size on the 20/40 line of an eye chart would be able to be seen by a patient with normal (20/20) vision at a testing distance of 40 feet, but for a patient with reduced vision (e.g. 20/40) the letter would need to be moved closer (to 20 feet) in order to be seen. When reading an eyechart in an ophthalmology exam room, mirrors are used to simulate a 20 foot testing distance (as the room is typically much shorter than 20 feet in length).

Visual acuity is expressed as 20/20, 20/40 up to about 20/800. Vision worse than that is often expressed qualitatively as:
CF- Count Fingers
HM- Hand Motion
LP- Light Perception
NLP- No Light Perception Source: Regenstrief Help

Uncorrected visual acuity is a measurement of clearness of vision while the patient is not using refractive correction. Best corrected visual acuity is acuity measurement using corrective lenses, if usually worn. Visual acuity measured using a Snellen Eye Chart is reported with a numerator of the standard testing distance of 20 and a denominator indicating the distance at which strokes of the smallest letter size viewable subtend at 1 minute of arc. (e.g., 20/10: with a standard testing distance of 20 feet, the strokes of the smallest letter size viewable would subtend 1 minute of arc at 10 feet, or as more commonly explained, what the patient can see at 20 feet, the average population can see at 10 feet). If unable to read letters on a testing chart, visual acuity is described as ranging from ability to count fingers, recognize hand motion, perceive bright light, or unable to perceive light. Source: Regenstrief LOINC

Basic Part Properties

Part Display Name
Visual acuity
Part Type
Component (Describes the core component or analyte measured)
Created On
2008-11-07
Construct for LOINC Short Name
VA

LOINC Terminology Service (API) using HL7® FHIR® Get Info

CodeSystem lookup
https://fhir.loinc.org/CodeSystem/$lookup?system=http://loinc.org&code=LP73686-5

Language Variants Get Info

Tag Language Translation
ru-RU Russian (Russian Federation) Зрение острота
zh-CN Chinese (China) 视力
Synonyms: 视觉敏锐度
it-IT Italian (Italy) Acuità visiva