II. Precautions
- Visual Acuity is THE Vital Sign of the eye
III. Exam: Distance Vision
- Vision with each eye individually and together
- Appropriate chart (usually 20 foot distance or 6 meters to chart, or half-length at 10 feet or 3 meters)
- Snellen Letters (6 years and older, adults)
- Snellen Numbers (Non-english speaking or illiterate)
- Tumbling E (Children ages 3 to 5 years)
- HOTV Card (Children ages 3 to 5 years)
- Picture Tests (Childen ages 3 to 5 years)
- Alternative handheld chart (Rosenbaum Chart)
- Interpretation
- Vision is recorded based on the smallest print letters the patient can read with half the answers correct
- Vision recorded as 20/X-Y
- Where 20 refers to feet from chart
- Where X refers to the distance a person with normal Vision can still read the same line
- Where Y refers to the number of missed items for the particular line
-
Myopia suggested if Vision improves with pinhole
- Vision testing through a small pinhole corrects for Refractive Errors
- Consider pinhole for Vision testing in a patient who did not bring their glasses to evaluation
- If Vision less than 20/200, assess best Vision with:
- Finger Counting (CF) at 1 foot and at 6 inches
- Hand Movements (HM)
- Light Perception (LP)
- No light Perception (NLP): total blindness
IV. Interpretation: Normal Vision for children 2.5 to 6 years
- Month 30-35: 20/60 (or 6/20) or better
- Month 36-47: 20/50 (or 6/15) or better
- Month 48-59: 20/40 (or 6/12) or better
- Month 60-72: 20/30 (or 6/10) or better
- Pan (2009) Opto Vis Sci 86(6): 607-12 [PubMed]
V. Management: Indications for referral to eye care specialist
- Indications for adults
- See Preventive Eye Examination for screening guidelines (e.g. Glaucoma)
- Uncorrected Vision <20/50 or
- One line difference (on Snellen Chart) between eyes
- Indications for children
- Any Age: Two line difference between eyes
- Example: OD 20/25 and OS 20/40
- Age 3-4: Either eye worse than 20/50
- Age 4-5: Either eye worse than 10/20 or 20/40
- Age >5: Either eye worse than 10/15 or 20/30 (<3 of 5 characters correct)
- References
- Any Age: Two line difference between eyes
VI. Exam: Near Vision
- Not generally screened
- Presbyopia occurs after age 40 years
VII. Exam: Refraction
- Performed by Optometry or Ophthalmology
- Measures optical error of eyes to prepare lenses
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Related Studies
| 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 |
| Russian | ZRENIIA OSTROTA, ЗРЕНИЯ ОСТРОТА |
| Croatian | VIDNA OŠTRINA |
| 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 |
