Skip to main content
Fig. 2 | Eye and Vision

Fig. 2

From: Possible limits of calibrating reading charts with the Landolt ring: a microscopic study

Fig. 2

Landolt ring near vision chart from Precision Vision (left column) and Landolt rings graphically optimized for print quality (right column; RADNER optimized); original magnification, ×40. Photographs of Landolt rings taken of print sizes ranging from 0.1 to − 0.3 logMAR. Nominal sizes are given between the columns. The Landolt ring near vision charts of Precision Vision show deficiencies in print quality and aberrations in the optotype heights, thicknesses of the lines, and widths of the openings. The endings that configure the opening of the Landolt rings are parallel from 0.0 to 0.1 logMAR, but the lines are blurred. The heights of the Landolt rings are within the 5% tolerance at all sizes. The openings are narrower, and the widths of the lines are wider than the nominal values (outside 5%). The Landolt rings optimized for printed quality show the best print quality. The edges of the lines are sharp, and the endings at the openings are clearly parallel. The Landolt rings closely match the nominal values in height and line width. Only two openings are outside the 5% tolerance, i.e., − 0.1 and 0.1 logMAR

Back to article page