Reading charts in logarithmic scale: why the Jaeger test is obsolete in the present?

Abstract

Seeing clearly from a distance close to our nose, to the end of our outstretched arms, is relevant during a large part of a human being’s day. Being able to read is a frequent activity for most people. Assessing near vision is part of the daily work of an ophthalmologist. Knowing what is the maximum performance of a patient’s near visual capacity allows us not only to detect ocular pathologies, but also aspects related to neurodegenerative processes. Nowadays, the correct measurement of near vision requires the use of charts developed on a logarithmic scale, which are standardized at international level. In this paper some historical aspects will be reviewed and the current characteristics of logarithmic scale reading charts will be described, with the aim of stimulating their use in the daily clinical practice, also explaining the existing differences between the use of the Jaeger test and the new Byromat reading char.