Penn State’s Philip Garvey, with the assistance of Wie-Yen Eie and Jennifer Klenna, conducted a study to determine which fonts are the most legible. Sixty-four subjects from 19-87 years of age viewed 64 displays using 33 fonts shown on a computer monitor. The results of this study appear in different formats. One report was published in the inaugural issue of “The Interdisciplinary Journal of Signage and Wayfinding,” which is published twice a year by the Academic Advisory Council for Signage Research and Education.
You can read it here: https://ijsw.shareok.org/home/article/view/3. A shorter synopsis of the study can be found on this website at http://fasi.org/2016/07/12/penn-state-study-examines-font-legibility/. The study was funded by Gemini, Inc., a Minnesota manufacturer of individual, 3-D letters.