https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/14293989Edit ImageSaveSaveEditCropCustom TextChanging Fixation from 1 to 4 requires 4 1/2 prism diopters of Positive Convergence. by Keystone View Co and Underwood and UnderwoodOriginal public domain image from Getty MuseumMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 1200 x 611 px | 300 dpiLarge JPEG 3500 x 1782 px | 300 dpiBest Quality JPEG 6639 x 3381 px | 300 dpiFree DownloadChanging Fixation from 1 to 4 requires 4 1/2 prism diopters of Positive Convergence. by Keystone View Co and Underwood and UnderwoodMore