Bach M. Visual acuity “cheat sheet” for high and low vision [Internet]. Freiburg (Germany): Michael Bach; 2017 Oct 20 [updated 2026 Jun 11; cited 2026 Jun 13]. Available from: https://michaelbach.de/sci/acuity.html
Beck RW, Moke PS, Turpin AH, Ferris FL 3rd, SanGiovanni JP, Johnson CA, Birch EE, Chandler DL, Cox TA, Blair RC, Kraker RT. A computerized method of visual acuity testing: adaptation of the early treatment of diabetic retinopathy study testing protocol. Am J Ophthalmol. 2003 Feb;135(2):194-205. doi: 10.1016/s0002-9394(02)01825-1. PMID: 12566024.
Early Treatment Diabetic Retinopathy Study design and baseline patient characteristics. ETDRS report number 7. Ophthalmology. 1991 May;98(5 Suppl):741-56. doi: 10.1016/s0161-6420(13)38009-9. PMID: 2062510.
de Jong PTVM. A history of visual acuity testing and optotypes. Eye (Lond). 2024 Jan;38(1):13-24. doi: 10.1038/s41433-022-02180-6. Epub 2022 Aug 3. Erratum in: Eye (Lond). 2024 Jan;38(1):226. doi: 10.1038/s41433-023-02612-x. PMID: 35922542; PMCID: PMC10764321.
Radner W. Toward an internationally accepted standard for reading charts. Prog Retin Eye Res. 2024 Jul;101:101262. doi: 10.1016/j.preteyeres.2024.101262. Epub 2024 Apr 2. PMID: 38574851.
IHE Eye Care Domain. General Eye Evaluation (GEE) [Internet]. IHE; 2012. Available from: http://www.ihe.net/Technical_Framework/upload/IHE_EyeCare_Supp_GEE_Rev1-1_TI_2012-06-29.pdf
Royal College of Ophthalmologists. Cataract National Dataset for Adults [Internet]. 2011. Available from: http://www.rcophth.ac.uk/page.asp?section=583§ionTitle=Cataract+National+Data+Set+for+Adults
Laidlaw D a. H, Tailor V, Shah N, Atamian S, Harcourt C. Validation of a computerised logMAR visual acuity measurement system (COMPlog): comparison with ETDRS and the electronic ETDRS testing algorithm in adults and amblyopic children. Br J Ophthalmol [Internet]. 2008 Feb 1 [cited 2012 Sep 26];92(2):241–4. Available from: http://bjo.bmj.com/content/92/2/241
Chiang MF, Boland MV, Brewer A, Epley KD, Horton MB, Lim MC, et al. Special Requirements for Electronic Health Record Systems in Ophthalmology. Ophthalmology [Internet]. 2011 Aug [cited 2012 Sep 26];118(8):1681–7. Available from: http://www.aaojournal.org/article/S0161-6420(11)00374-5/abstract
Chen DZ, Tham YC, Shen L, Chee SP. A Comparative Validation Study of Near Visual Acuity Assessment Using Different Handheld Acuity Charts. Ophthalmol Sci. 2025 Apr 8;5(5):100790. doi: 10.1016/j.xops.2025.100790. PMID: 40469897; PMCID: PMC12135357.
Organisation: Ocean Informatics, UK
Email: ian.mcnicoll@oceaninformatics.com
Date originally authored: 2012-07-18
Organisation: Ocean Informatics, UK
Email: ian.mcnicoll@oceaninformatics.com
Date originally authored: 2012-07-18
- Licence: This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/.
- Custodian Organisation: openEHR Foundation
- References: Elliott DB. The good (logMAR), the bad (Snellen) and the ugly (BCVA, number of letters read) of visual acuity measurement. Ophthalmic Physiol Opt. 2016 Jul;36(4):355-8. doi: 10.1111/opo.12310. PMID: 27350181. Bach M. Visual acuity “cheat sheet” for high and low vision [Internet]. Freiburg (Germany): Michael Bach; 2017 Oct 20 [updated 2026 Jun 11; cited 2026 Jun 13]. Available from: https://michaelbach.de/sci/acuity.html Beck RW, Moke PS, Turpin AH, Ferris FL 3rd, SanGiovanni JP, Johnson CA, Birch EE, Chandler DL, Cox TA, Blair RC, Kraker RT. A computerized method of visual acuity testing: adaptation of the early treatment of diabetic retinopathy study testing protocol. Am J Ophthalmol. 2003 Feb;135(2):194-205. doi: 10.1016/s0002-9394(02)01825-1. PMID: 12566024. Early Treatment Diabetic Retinopathy Study design and baseline patient characteristics. ETDRS report number 7. Ophthalmology. 1991 May;98(5 Suppl):741-56. doi: 10.1016/s0161-6420(13)38009-9. PMID: 2062510. de Jong PTVM. A history of visual acuity testing and optotypes. Eye (Lond). 2024 Jan;38(1):13-24. doi: 10.1038/s41433-022-02180-6. Epub 2022 Aug 3. Erratum in: Eye (Lond). 2024 Jan;38(1):226. doi: 10.1038/s41433-023-02612-x. PMID: 35922542; PMCID: PMC10764321. Radner W. Toward an internationally accepted standard for reading charts. Prog Retin Eye Res. 2024 Jul;101:101262. doi: 10.1016/j.preteyeres.2024.101262. Epub 2024 Apr 2. PMID: 38574851. IHE Eye Care Domain. General Eye Evaluation (GEE) [Internet]. IHE; 2012. Available from: http://www.ihe.net/Technical_Framework/upload/IHE_EyeCare_Supp_GEE_Rev1-1_TI_2012-06-29.pdf Royal College of Ophthalmologists. Cataract National Dataset for Adults [Internet]. 2011. Available from: http://www.rcophth.ac.uk/page.asp?section=583§ionTitle=Cataract+National+Data+Set+for+Adults Laidlaw D a. H, Tailor V, Shah N, Atamian S, Harcourt C. Validation of a computerised logMAR visual acuity measurement system (COMPlog): comparison with ETDRS and the electronic ETDRS testing algorithm in adults and amblyopic children. Br J Ophthalmol [Internet]. 2008 Feb 1 [cited 2012 Sep 26];92(2):241–4. Available from: http://bjo.bmj.com/content/92/2/241 Chiang MF, Boland MV, Brewer A, Epley KD, Horton MB, Lim MC, et al. Special Requirements for Electronic Health Record Systems in Ophthalmology. Ophthalmology [Internet]. 2011 Aug [cited 2012 Sep 26];118(8):1681–7. Available from: http://www.aaojournal.org/article/S0161-6420(11)00374-5/abstract Chen DZ, Tham YC, Shen L, Chee SP. A Comparative Validation Study of Near Visual Acuity Assessment Using Different Handheld Acuity Charts. Ophthalmol Sci. 2025 Apr 8;5(5):100790. doi: 10.1016/j.xops.2025.100790. PMID: 40469897; PMCID: PMC12135357.
- Original Namespace: org.openehr
- Original Publisher: openEHR Foundation
- Custodian Namespace: org.openehr
- MD5-CAM-1.0.1: E812018A64E707434A35C6654E931F14
- Build Uid: 76a9f7a8-fe1a-474c-847a-5a57f29df20a
- Ip Acknowledgements: This artefact includes content from SNOMED Clinical Terms® (SNOMED CT®) which is copyrighted material of the International Health Terminology Standards Development Organisation (IHTSDO). Where an implementation of this artefact makes use of SNOMED CT content, the implementer must have the appropriate SNOMED CT Affiliate license - for more information contact https://www.snomed.org/snomed-ct/get-snomed or info@snomed.org.
- Revision: 0.0.1-alpha
Where multiple devices are positioned in front of the same eye, this cluster is expected to be used once for each.
For monocular tests where the partner eye is fully occluded, the assumption is that the visual aid is positioned in front of the eye being tested. In these circumstances autopopulation from the 'Eye examined' element is possible.
- Left eye [The left eye was examined.]
[SNOMED-CT::726675003 | Structure of left eye region] - Right eye [The right eye was examined.]
[SNOMED-CT::726680007 | Structure of right eye region]
Avoid using the generic value "Corrected" where the device or provenance of corrective values are known. Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
Choice of:
Coded Text- Autorefraction-based correction [A correction with powers based on an autorefraction test.]
- Subjective refraction-based correction [A correction with powers based on a subjective refraction.]
- Glasses [Eyeglasses.]
- Rigid contact lens [A contact lens with a rigid optical center, including hybrid lenses.]
- Soft contact lens [A soft contact lens with a soft optical center.]
- Retinoscopy based correction [A correction with powers based on a retinoscopy test.]
- Corrected [Lenses without a known provenance or source of the powers.]
- Fogging lens [A lens used to intentionally blur the vision in that eye while the other eye is tested.]
- Pinhole occluder [A device with one or multiple small holes acting as apertures.]
- Subjective overrefraction-based correction [A correction with values based on subjective overrefraction was used.]
- Unaided [There is explicitly nothing in front of the eye during the visual acuity testing, also referred to as "uncorrected".]
- Defocus lens [A lens used with the intention of adding refractive error.]
Text
- Cycloplegic refraction [The correction used was based on a measurement of refractive error in a cycloplegic state.]
- Non-cycloplegic refraction [The correction used was based on a measurement of refractive error in a non-cycloplegic state.]
Used as the base correction upon which cylinder and axis are applied.
Property: Refractive power
Units: dioptre
Property: Refractive power
Units: dioptre
By convention, the axis of the cylinder is defined by its meridian of zero power.
Property: Angle, plane
Units: °
Property: Refractive power
Units: dioptre
Include:
openEHR-EHR-CLUSTER.device.v1 and specialisations
The physical examination of the eye will be recorded using the CLUSTER.exam-eye family of archetypes. Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
Choice of:
- Coded Text
- Normal [The pupil is in its natural physiological state without pharmacological intervention or pathological changes.]
- Medically induced mydriasis [The pupil was dilated due to prior administration of mydriatic agents.]
- Medically induced miosis [The pupil was constricted due to prior administration of miotic agents.]
- Pathological pupil state [The pupil was in an unphysiological state due to disease, trauma, or structural abnormalities.]
- Text
Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
- Glare light [A light source, or multiple light sources were directed at the eye to induce glare.]
- Brightness Acuity Test [A handheld ganzfeld illumination device was used to simulate environmental brightness.]
Include:
openEHR-EHR-CLUSTER.vision_
This is a categorical description of the individual's presumed retinal adaptation state, not a measurement of the ambient lighting.
- Photopic [The individual is adapted to high luminance conditions.]
- Mesopic [The individual is in a transitional adaptation state between photopic and scotopic.]
- Scotopic [The individual is adapted to low luminance conditions.]
Property: Illuminance
Units: lx
Candela per square meter is equivalent to the non-SI unit 'nit'.
Units: cd/m2
Examples: 'Patient was confused', "Lid held open by hand" "Eccentric Fixation".
For example: local information requirements or additional metadata to align with FHIR or CIMI equivalents.
Include:
All not explicitly excluded archetypes
'Both eyes' may only be used for test of binocular visual acuity.
- Left eye [The left eye was examined.]
[SNOMED-CT::726675003 | Structure of left eye region] - Right eye [The right eye was examined.]
[SNOMED-CT::726680007 | Structure of right eye region] - Both eyes [Both eyes were examined simultaneously.]
[SNOMED-CT::362508001 | Both eyes, entire]
Typically, only one result should be populated. Converted or derived values should be stored in the appropriate element in the 'Derived result' cluster.
Do not use this element unless the visual acuity was initially recorded in LogMAR notation. Sometimes referred to as 'logRAD' in reading acuity tests.
Units: 1{logMAR}
For Snellen ratios, a distance of 6 metres is typically used as the reference distance (numerator). For M-Scale notation, the numerator is equal to the real testing distance. To avoid ambiguity, populate the 'Testing distance' element if M-Scale notation is used, and generally whenever possible.
- Fraction
Denominator: >0.0..99999.0
A reference distance of 20 feet is often used as the default numerator, even when it is not the real testing distance. Use of the 'Testing distance' element is encouraged to avoid ambiguity.
- Fraction
Denominator: >0.0..99999.0
Units: >0.0..999.0 1{decimal VA}
Limit decimal places: 3
Caution: The 30 letters presumed readable at 1m distance are added to the results of testing at 4m distance. See ETDRS report number 7 in References. A letter score of 85 is equivalent to 20/20, 1.0 decimal, 0.0 logMAR.
min: >=0; max: <=999
Defined as 5 minus the LogMAR result, part of the Chinese national standard GB11533-1989.
Units: 1{5PointVA}
Strictly not a unit of visual acuity but a measure of stimulus size.
1.0: N 1 [N font size 1.]
1.5: N 1.5 [N font size 1.5.]
2.0: N 2 [N font size 2.]
2.5: N 2.5 [N font size 2.5.]
3.0: N 3 [N font size 3.]
3.5: N 3.5 [N font size 3.5.]
4.0: N 4 [N font size 4.]
4.5: N 4.5 [N font size 4.5.]
5.0: N 5 [N font size 5.]
5.5: N 5.5 [N font size 5.5.]
6.0: N 6 [N font size 6]
6.5: N 6.5 [N font size 6.5.]
7.0: N 7 [N font size 7.]
7.5: N 7.5 [N font size 7.5.]
8.0: N 8 [N font size 8.]
9.0: N 9 [N font size 9.]
10.0: N 10 [N font size 10.]
11.0: N 11 [N font size 11.]
12.0: N 12 [N font size 12.]
13.0: N 13 [N font size 13.]
14.0: N 14 [N font size 14.]
15.0: N 15 [N font size 15.]
16.0: N 16 [N font size 16.]
18.0: N 18 [N font size 18.]
20.0: N 20 [N font size 20.]
22.0: N 22 [N font size 22.]
24.0: N 24 [N font size 24.]
26.0: N 26 [N font size 26.]
28.0: N 28 [N font size 28.]
30.0: N 30 [N font size 30.]
32.0: N 32 [N font size 32.]
36.0: N 36 [N font size 36.]
40.0: N 40 [N font size 40.]
42.0: N 42 [N font size 42.]
44.0: N 44 [N font size 44.]
48.0: N 48 [N font size 48.]
54.0: N 54 [N font size 54.]
56.0: N 56 [N font size 56.]
60.0: N 60 [N font size 60.]
66.0: N 66 [N font size 66.]
72.0: N 72 [N font size 72.]
Strictly not a unit of visual acuity but a measure of stimulus size.
1.0: J1 [Jaeger font size 1.]
2.0: J2 [Jaeger font size 2.]
3.0: J3 [Jaeger font size 3.]
4.0: J4 [Jaeger font size 4.]
5.0: J5 [Jaeger font size 5.]
6.0: J6 [Jaeger font size 6.]
7.0: J7 [Jaeger font size 7.]
8.0: J8 [Jaeger font size 8.]
9.0: J9 [Jaeger font size 9.]
10.0: J10 [Jaeger font size 10.]
11.0: J11 [Jaeger font size 11.]
12.0: J12 [Jaeger font size 12.]
13.0: J13 [Jaeger font size 13.]
14.0: J14 [Jaeger font size 14.]
15.0: J15 [Jaeger font size 15.]
16.0: J16 [Jaeger font size 16.]
17.0: J17 [Jaeger font size 17.]
18.0: J18 [Jaeger font size 18.]
19.0: J19 [Jaeger font size 19.]
20.0: J20 [Jaeger font size 20.]
Strictly not a unit of visual acuity but a measure of stimulus size.
Units: >0.0..9999.0 1/cm
Used in grating based tests such as Teller acuity cards.
Units: >0.0..9999.0 1/deg
Not to be used for light projection testing. Use OBSERVATION.light_projection_test archetype for this purpose. Higher ordinal values represent better visual function.
1: No light perception [The individual was unable to identify the absence or presence of light.]
2: Light perception [The individual correctly identified the absence or presence of light.]
3: Hand Movement [The individual perceived hand movements.]
4: Count Fingers [The individual correctly counted fingers.]
Choice of:
Count
min: >=-9; max: <=9- Coded Text
- Partial [Some symbols were not read correctly in the smallest line that was scored as being successfully read.]
- Ratio
- Fraction
- Ratio
- Fraction
Typically in study settings, this score describes either the number of optotypes identified (letters read): 1. Out of 30 at 1m distance. Or 2. Out of 70 at 4m distance. In which case the 30 letters from the 1m distance are added to the result as they are presumed readable. Typically, an ETDRS letter score of 85 is equivalent to 20/20, 1.0 decimal, 0.0 logMAR. Conversion of this notation requires precise understanding of testing procedures and intended meaning.
Property: null
Units: arb. unit
Examples include specifying the card scored in a Cardiff acuity test, or supplementary results on reading visual acuity tests.
Include:
openEHR-EHR-CLUSTER.cardiff_
openEHR-EHR-CLUSTER.reading_
Boundary definitions may vary, therefore population of the 'Testing distance' is encouraged, especially for Intermediate or near distances.
- Near [The test was performed at near distance.]
- Intermediate [The test was performed at intermediate distance.]
- Far [The test was performed at far distance.]
The stimulus may be a virtual image.
Property: Length
Units:
- >0.0..999.0 m
Limit decimal places: 3 - 0.0..9999.0 cm
Limit decimal places: 1 - >0.0..9999.0 in
Limit decimal places: 2 - >0.0..9999.0 ft
Limit decimal places: 2
Reading visual acuity expressed LogMAR is sometimes referred to as LogRAD. Supplementary results of reading Visual acuity tests can be recorded via the 'supplementary results' slot.
- Minimum resolvable visual acuity [A measurement of the ability to distinguish two separate objects as distinct.]
- Reading visual acuity [A measurement of the smallest visual angle at which text can be read.]
Allows for the capture of basic information where additional detail about the type or device name of the stimulus are unknown.
- Printed chart or card [A printed chart or card.]
- Electronic chart display [An electronic display.]
- Projected chart [A chart projector.]
- Physical object [Physical objects other than charts or cards.]
- Integrated virtual chart display [A chart presented as a virtual image inside a device, such as an autorefractor.]
Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
Choice of:
- Coded Text
- logMAR chart [A logMAR chart was used.]
- Snellen chart [A Snellen chart was used.]
[SNOMED-CT::400913005 | Snellen chart] - ETDRS chart [An ETDRS chart was used.]
[SNOMED-CT::400914004 | ETDRS visual acuity chart] - Golovin-Sitsev table [A Golovin-Sitsev table was used.]
- Monoyer chart [A monoyer visual acuity chart was used.]
- Cardiff acuity cards [Cardiff acuity cards were used.]
- Keeler acuity cards [Keeler acuity cards were used.]
- Berkeley rudimentary vision test [Berkeley rudimentary vision test was used.]
- Near reading card [A near card with segments of text that are read by the individual was used.]
- LEA grating acuity test [LEA gratings, a type of preferential looking test, was used.]
- Teller acuity cards [Teller acuity cards were used.]
- Cardiff acuity test [A Cardiff acuity test was used.]
- Allen picture test [An Allen picture test was used.]
- Sheridan letter test [A Sheridan letter test was used.]
- Cambridge crowding cards [A Cambridge crowding card test was used.]
- MNREAD chart [A MNREAD acuity chart was used.]
- Radner Reading chart [A Radner reading chart was used.]
- Freiburg visual acuity test [A Freiburg visual acuity test was used.]
- Sheridan Gardiner test [A Sheridan Gardiner test was used.]
- Sonksen Silver test [A Sonksen Silver test was used.]
- Text
Include:
openEHR-EHR-CLUSTER.device.v1 and specialisations
Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
- Pictogram [Picture optotypes were used.]
- Orientation-Type Optotypes [Orientation-Type optotypes were used.]
- Letters [Letter optotypes were used.]
- Numbers [Number optotypes were used.]
- Lea Symbols [Lea symbol optotypes were used.]
- Kay picture [Kay picture optotypes were used.]
- Allen picture [Allen picture optotypes were used.]
- Auckland [Auckland optotypes were used.]
- Amsterdam picture [Amsterdam picture optotypes were used.]
- Landolt C [Landolt C optotypes were used.]
- Tumbling E [Tumbling E optotypes were used.]
- Lea numbers [Lea number optotypes were used.]
- Sloan letters [Sloan letter optotypes were used.]
- Cyrillic letters [Cyrillic letter optotypes were used.]
- Snellen letters [Snellen letter optotypes were used.]
- HOTV letters [HOTV letter optotypes were used.]
- LRVC letters [LRVC letter optotypes were used.]
- British letters (2003) [British letter (2003) optotypes were used.]
- European-wide letters [European-wide letter optotypes were used.]
Additional detail on the degree of crowding, and presence of crowding bars can be recorded using the 'Optotype presentation details' SLOT.
- Crowded [The stimulus was presented in a manner thought to induce a crowding effect.]
- Not Crowded [The stimulus was presented in a manner thought to induce no crowding effect.]
Include:
openEHR-EHR-CLUSTER.optotype_
Note that the majority of visual acuity tests are performed under high contrast conditions. Where possible, population of quantitative elements on contrast is encouraged.
- High-contrast [The test was performed with high contrast.]
- Low-contrast [The test was performed with low contrast.]
Used where a determination of the exact visual acuity with the additional correction (in another event) was not performed, typically because it was deemed irrelevant for lack of improvement. Coding with a terminology is recommended. Free text entry should only be permitted if no appropriate coded value is available.
Choice of:
- Coded Text
- NI with additional pinhole [No improvement with an additional pinhole placed in front of the tested eye.]
- NI with subjective refraction-based correction [No improvement with corrective lenses based on subjective refraction.]
- NI with autorefraction-based correction [No improvement with corrective lenses based on an autorefraction test.]
- NI with retinoscopy-based correction [No improvement with corrective lenses based on retinoscopy.]
- NI with glasses [No improvement with eyeglasses.]
- NI with soft contact lens [No improvement with a soft contact lens.]
- NI with rigid contact lens [No improvement with a hard contact lens.]
- NI with further correction [No improvement with an unspecified further correction.]
- Text
It is a common but controversial practice to comment "partial" where the last line was not read entirely even in line-based scoring. This is covered by the "Letters missed or read in addition to scored line" element.
Not to be used for information about how the test was performed or patient circumstances affecting result.
These classifiers do not contain information on the actual correction used and they are used with significant variability in different settings. It is encouraged to record the specific aids used within 'Visual aid per eye' clusters.
Choice of:
- Coded Text
- BCVA [This result is classified as a Best Corrected Visual Acuity.]
- BRVA [This result is classified as a Best Recorded Visual Acuity.]
- Text
Include:
openEHR-EHR-CLUSTER.exclusion_
Severin Kohler, Germany
Lars Fuhrmann, Germany (Editor)
Bill Aylward, openEyes Project, UK
Gustavo Bacelar-Silva, Brazil (Editor)
Stephen Chu, NeHTA, Australia
Alistair Laidlaw, Guys and St Thomas NHS Trust, UK
Heather Leslie, Ocean Informatics, Australia
Gustavo M Bacelar-Silva, Brazil
Mike Mair, Timaru Eye Clinic, New Zealand
Ian McNicoll, Ocean Informatics, United Kingdom (Editor)
- Norwegian Bokmål: Ingrid Heitmann, Arne Løberg Sæter, Oslo universitetssykehus HF, iheitman@ous-hf.no, arnelsa@gmail.com
- Spanish (Chile): Poblete Francisco, DuocUC, openehrfpoblete@gmail.com, .