Reporting the visual acuity of groups: the relation among alternate measures.

There are often large disparities in the way in which visual acuities are reported for groups. A survey of 156 reports published within the last 5 years shows that some researchers report binocular acuity, others best eye, monocular, or mean monocular acuities. Some of these measures may be confounded further with accommodation distance. To ascertain the relation among the various measures of acuity reported commonly, data were obtained from 702 observers. The results indicate that there is a high degree of concordance among the various measures used to report the visual acuity of groups, with many of the correlations in the 0.9 range. It is further shown that a composite measure, based upon mean binocular or best eye acuity, may be a useful means of conveying group differences in visual resolution.