II. Precautions

  1. Visual Acuity is THE Vital Sign of the eye
    1. Obtain Visual Acuity on all patients with eye complaints
    2. Obtain before remainder of exam (e.g. flashlight tests, topical agents, Mydriatic use)
    3. In acute eye complaints, perform Visual Acuity with their Vision correction (e.g. glasses)

III. Exam: Distance Vision

  1. Vision with each eye individually and together
  2. Appropriate chart (usually 20 foot distance or 6 meters to chart, or half-length at 10 feet or 3 meters)
    1. Snellen Letters (6 years and older, adults)
    2. Snellen Numbers (Non-english speaking or illiterate)
    3. Tumbling E (Children ages 3 to 5 years)
    4. HOTV Card (Children ages 3 to 5 years)
    5. Picture Tests (Childen ages 3 to 5 years)
  3. Alternative handheld chart (Rosenbaum Chart)
    1. Rosenbaum Chart held 16 inches (or 36 cm) away from patient's eyes
    2. Evaluates near Vision (in contrast to standard chart at 20 feet, which evaluates distance Vision)
  4. Interpretation
    1. Vision is recorded based on the smallest print letters the patient can read with half the answers correct
    2. Vision recorded as 20/X-Y
      1. Where 20 refers to feet from chart
      2. Where X refers to the distance a person with normal Vision can still read the same line
      3. Where Y refers to the number of missed items for the particular line
  5. Myopia suggested if Vision improves with pinhole
    1. Vision testing through a small pinhole corrects for Refractive Errors
    2. Consider pinhole for Vision testing in a patient who did not bring their glasses to evaluation
  6. If Vision less than 20/200, assess best Vision with:
    1. Finger Counting (CF) at 1 foot and at 6 inches
    2. Hand Movements (HM)
    3. Light Perception (LP)
    4. No light Perception (NLP): total blindness

IV. Interpretation: Normal Vision for children 2.5 to 6 years

  1. Month 30-35: 20/60 (or 6/20) or better
  2. Month 36-47: 20/50 (or 6/15) or better
  3. Month 48-59: 20/40 (or 6/12) or better
  4. Month 60-72: 20/30 (or 6/10) or better
  5. Pan (2009) Opto Vis Sci 86(6): 607-12 [PubMed]

V. Evaluation: Indications for referral to eye care specialist

  1. Indications for adults
    1. See Preventive Eye Examination for screening guidelines (e.g. Glaucoma)
    2. Uncorrected Vision <20/50 or
    3. One line difference (on Snellen Chart) between eyes
  2. Indications for children
    1. Age 4-5: Either eye worse than 10/20 or 20/40
    2. Age >5: Either eye worse than 10/15 or 20/30
    3. Two line difference between eyes
      1. Example: OD 20/25 and OS 20/40
    4. Reference
      1. (2003) Pediatrics 111:903 [PubMed]

VI. Exam: Near Vision

  1. Not generally screened
  2. Presbyopia occurs after age 40 years

VII. Exam: Refraction

  1. Performed by Optometry or Ophthalmology
  2. Measures optical error of eyes to prepare lenses

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Related Studies

Ontology: Visual Acuity (C0042812)

Definition (MSH) Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
Definition (NCI) Sharpness of vision, the ability to discern fine detail.
Definition (PSY) The ability or capacity of an observer to perceive fine detail.
Concepts Clinical Attribute (T201)
MSH D014792
SnomedCT 83760008, 363983007
LNC MTHU013695
English Acuities, Visual, Acuity, Visual, Visual Acuities, visual acuity, acuity visual, Visual Acuity, Visual acuity, function (observable entity), Visual acuity (biological function), Visual acuity, Visual acuity (observable entity), Resolving power of eye, Visual acuity, NOS, Visual acuity (qualifier value), VA - Visual acuity
Swedish Synskärpa
Czech zraková ostrost
Finnish Näöntarkkuus
Italian Acutezza visiva, Acuità visiva, Visus
Polish Ostrość wzroku
Norwegian Synsskarphet, Visuell skarphet
Spanish agudeza de la visión, agudeza de la visión (entidad observable), Acuidad Visual, agudeza de la visión (calificador), agudeza visual (entidad observable), agudeza visual, poder de resolución del ojo, Agudeza Visual
French Acuité visuelle
German Visus, Sehschärfe
Dutch Gezichtsscherpte, Visus
Portuguese Acuidade Visual

Ontology: Snellen chart (C0183370)

Definition (UMD) Eye charts designed to be used in measuring visual acuity using a sheet of paper on which rows of standard symbols of different sizes are printed. The symbols can be shaped letters (e.g. block letters, letter E), numbers, or outlines of objects. Visual acuity is measured by the smallest row of symbols a person standing at a certain distance can identify (each row is marked with a distance value). Projectors or monitor screens indicating the ophthalmic symbols are also used for this purpose. Visual acuity eye charts are used mainly for vision screening in healthcare facilities, at ophthalmologist offices, and in the field.
Definition (SPN) A visual acuity chart is a device that is a chart, such as a Snellen chart with block letters or other symbols in graduated sizes, intended to test visual acuity.
Concepts Medical Device (T074)
SnomedCT 421763006, 400913005
English CHART, VISUAL ACUITY, Visual acuity chart (physical object), Visual acuity chart, Charts, Eye, Visual Acuity, Snellen Eye Charts, Optotype Eye Charts, snellen eye chart, acuity charts visual, visual acuity chart, snellen chart, Snellen chart (physical object), Snellen chart, Snellen eye chart
Spanish tabla para evaluar agudeza visual (objeto físico), tabla para evaluar agudeza visual, carta de Snellen (objeto físico), carta de Snellen

Ontology: ETDRS visual acuity chart (C1275992)

Concepts Medical Device (T074)
SnomedCT 400914004
English ETDRS visual acuity chart (physical object), Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity chart, Early Treatment of Diabetic Retinopathy Study (ETDRS) visual acuity chart (physical object), Early Treatment of Diabetic Retinopathy Study visual acuity chart (physical object), Early Treatment of Diabetic Retinopathy Study visual acuity chart, ETDRS chart, ETDRS visual acuity chart, Early Treatment Diabetic Retinopathy Study chart
Spanish carta para agudeza visual en estudio para tratamiento temprano de la retinopatía diabética, carta para agudeza visual del Estudio para Tratamiento Temprano de la Retinopatía Diabética (objeto físico), carta para agudeza visual en estudio para tratamiento temprano de la retinopatía diabética (objeto físico), carta para agudeza visual del ETDRS, carta para agudeza visual del Estudio para Tratamiento Temprano de la Retinopatía Diabética, ETDRS visual acuity chart (physical object), ETDRS chart, Early Treatment Diabetic Retinopathy Study chart, ETDRS visual acuity chart

Ontology: HOTV cards (C1302979)

Concepts Medical Device (T074)
SnomedCT 400916002
English HOTV cards (physical object), HOTV cards
Spanish cartas de Hotv (objeto físico), cartas de Hotv