Fig. 1

C-Test Landolt ring test (left column) and Landolt rings of the near vision chart from the RADNER Charts (right column); original magnification, ×40. Photographs of Landolt rings taken of print sizes ranging from 0.1 to − 0.2 logMAR. Nominal sizes are given between the columns. The C-Test shows deficiencies in print quality and aberrations in the optotype heights, thicknesses of the lines, and widths of the openings. The shape of the Landolt rings and endings that configure the opening of the Landolt rings are distorted. The lines are blurred and frayed. The openings are too narrow; the heights and thicknesses of the lines are > 5% compared with the nominal values. The Landolt rings of the near vision charts from the RADNER charts are more accurate. The edges of the lines are sharper, and the endings that form the openings are in parallel. The heights are within the 5% tolerance, but the widths of the openings and lines lie outside that tolerance