[Measuring Visual Acuity].

This article reviews the basic physiology of visual acuity and the principles for its clinical measurement. It describes visual acuity and its limits as a function of the human eye. Referring to the new international standard ISO/FDIS8596:2017 it explains the conditions for standardized visual acuity testing. Furthermore, it gives detailed instruction on measuring visual acuity at distance and near, as well as in children, in low vision patients and for scientific purposes. Georg Thieme Verlag KG Stuttgart · New York.