The problem of an accurate assessment of visual acuity appeared to be so complicated that a solution satisfying both
visual scientists and optometrists had not been found up to date. In practical works, di erent methodological approaches
are used in parallel, each having its advantages and shortages. In theoretical investigations, only some partial aspects
of a general problem have been analyzed successfully. Unfortunately, in line with a signi cant progress in understanding
some principal points, in recent publications, one could notice controversies in using basic notions that hinder proper
analysis and comparison of the results obtained. In particular, this concerns the unit of visual acuity measurements.
During many years, traditionally, in most countries, di erent but easily comparable and rather natural notations of
Donders and Snellen were used. However, in recent years, there are more and more recommendations to use only LogMAR
since such “unit” provides a possibility to obtain more accurate data of visual acuity measurements and improve their
analysis. In this paper, we consider principal shortages of using LogMAR notation for scoring visual acuity measurements
though using logarithmic scale in elaboration of the test charts seems to be quite reasonable. The arguments are
presented in favor of the classical decimal notion of Donders with conventional standard measuring unit 1.0 since this
measure corresponds to the strict notion of resolution capability used for various systems of image processing and
transmission on the basis of maximal reproducible spatial frequency.
visual acuity, resolution capability, unit of measurement, decimal notation, LogMAR
Rozhkova G. I.
Logmar dlya ostroty zreniya khuzhe, chem loshadinaya sila dlya moshchnosti elektricheskoi lampochki
[Logmar for visual acuity is worse than horsepower for electric lamp].
Sensornye sistemy [Sensory systems].
P. 31-43 (in Russian).
- Beklemishev A.V. Measures and units of physical quantities. M.: 1963. 296 p. [in Russian].
- Volkov V.V., Kolesnikova L.N., Shelepin Ju.E. Frequency-contrast characteristics and visual acuity in ophthalmological practice // Ophthalmol. J. 1983. No 3. P. 148–151 [in Russian].
- Koskin S.A. The system of visual acuity assessment for medical expertise. MD thesis. SPb. 2009. 48 p. [in Russian].
- Pelevin V.F. Metrology and means of measurements. NIZ Infra-M, Nov. znan e. 2015. 272 p. [in Russian].
- Rozhkova G.I., Matveev S.G. Vision of children: the problems of assessment and functional treatment. M.: Nauka, 2007. 315 p. [in Russian].
- Sena L.A. Units of physical quantities and their dimentions. M.: Nauka, 1988. 431 p. [in Russian].
- Holina A. A new chart for visual acuity assessment // Russian Ophthalmol. J. 1930. V. 11. No 1. P. 42–47 [in Russian].
- Shamshinova A.M., Volkov V.V. Functional methods of investigations in ophthalmology. M.: Medicine, 1999. 416 p. [in Russian].
- Shelepin Ju. E., Kolesnikova L.N., Levkovich Ju.I. Visocontrastometry. L.: Nauka, 1985. 102 p. [in Russian].
- Bailey I.L., Lovie J.E. New design principles for visual acuity letter charts // Am.J. Optom. Physiol. Opt. 1976. V. 53. P. 740–745.
- Campbell F.W., Green D.G. Optical and retinal factors affecting visual resolution // J. Physiol. Lond. 1965. V.181, P. 576–593.
- Campbell F.W., Robson J.C. Application of Fourier analysis to the visibility of gratings // J. Physiol. 1968. V. 197. P. 551–566.
- Colenbrander A. (General Secretary, Visual Functions Committee, International Council of Ophthalmology) Visual acuity measurement standard // Italian J. Ophthalmol.1988. V. 2(1). P. 1–19.
- Colenbrander A. The Historical evolution of visual acuity measurement // Visual Impairment Research. 2008. V.10 (2–3). P. 57–66.
- Ferris F.L., Kasso A., Bresnick G.H., Bailey I. New visual acuity charts for clinical research // Am. J. Ophthalmol. 1982. V. 4 P. 91–96.
- Green J. On a new series of test-letters for determining the acuteness of vision // Transactions of the American Ophthalmological Society. 1868. V. 1(4–5). P. 68–71.
- Green J. Notes on the clinical determination of the acuteness of vision including the construction and graduation of optotypes // Trans. Am. Ophthalmol. Soc. 1905. V. 10. P. 644–654.
- Holladay J.T. Proper method for calculating average visual acuity // Journal of Refractive Surgery. 1997. V. 13 (4). P. 388–391.
- International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (3rd ed.), Joint Committee for Guides in Metrology. 2008. p. 6.
- ISO 8596. International Standard. Ophthalmic optics. Visual acuity testing. Standard optotype and its presentation. Geneve: International Standards Organization, 1994. (2nd edition: 2009).
- ISO 8597. International Standard. Optics and optical instruments. Visual acuity testing. Method of correlating optotypes. Geneve: International Standards Organization, 1994.
- ISO 5725-2. International Standard. Accuracy (trueness and precision) of measurement methods and results. Basic methods for the determination of repeatability and reproducibility of a standard measurement method. International Standards Organization, Geneva,1994.
- Kniestedt C., Stamper R.L. Visual acuity and its measurement // Ophthalmol. Clin. N. Am. 2003. V.16. P. 155–170.
- Landolt E. Méthode optométrique simple // Bulletins et Memoires de la Société Français d’Ophtalmologie. 1888. V. 6. P. 213–214.
- Ogle K.N. On the problem of an international nomenclature for designing visual acuity // Am.J. Ophthalmol. 1953. V. 36 (7). P. 909–921.
- Pirenne M.H. Visual acuity / In: The Eye. 1962. V. 2. P. 175–195.
- Recommended standard procedures for the clinical measurement and speci cation of visual acuity. Report of working group 39. Committee on vision. Assembly of Behavioral and Social Sciences, National Research Council, National Academy of Sciences, Washington, D. C. // Adv Ophthalmol. 1980;41:103–148.
- Rosser D.A., Cousens S., Murdoch I.E., Fitzke F.W., Laidlaw D.A. How sensitive to clinical change are ETDRS LogMAR visual acuity measurements? // Invest. Ophthalmol. Vis. Sci. 2003. V. 44. P, 3278– 3281.
- Sloan L.L. Needs for precise measures of acuity: equipment to meet these needs // Arch Ophthalmol. 1980. V. 98. P. 286–290.
- Snellen H. Test-types for the determination of the acuteness of vision. Utrecht: P. W. van de We er, 1862. 44 p.
- Virsu V., Rovamo J. Visual resolution, contrast sensitivity, and the cortical magni cation factor // Exp. Brain Res. 1979. V. 37. P. 475–494.
- Visual Impairments: Determining Eligibility for Social Security Bene ts. Tests of visual functions. Board on: The National Academies Press. Behavioral, Cognitive, and Sensory Sciences and Education (BCSSE). 2002.
- Westheimer G. Scaling of visual acuity measurements // Arch. Ophthalmol. 1979. V. 97. P. 327–330.
- Williams M. A., Moutray T. N., Jackson A.J. Uniformity of visual acuity measures in published studies // Invest. Ophthalmol. Vis. Sci. 2008. V.49 (10). P. 4321– 4327.