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LogMAR for visual acuity is worse than horsepower for electric lamp

© 2017 G. I. Rozhkova

Institute for Information Transmission Problems RAS (Kharkevich Institute) 127051 Moscow, B. Karetny per.19, Build. 1

Received 08 Aug 2016

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.

Key words: visual acuity, resolution capability, unit of measurement, decimal notation, LogMAR

Cite: 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]. 2017. V. 31(1). P. 31-43 (in Russian).


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