Impact of Font Style on Reading Parameters: Comparing Radner Reading Charts Printed in Times New Roman and Arial

Purpose To compare the effect of font type on reading parameters by using the ISO7921:2024 compliant RADNER Reading Charts printed in two fonts: Times New Roman PS (serif) and Arial MS (sans-serif). Methods A prospective cross-sectional study was conducted with 63 participants (native German speakers; mean age: 42.40 ± 14.65 years). Reading performance was evaluated binocularly with International Standards Organization (ISO) 7921:2024 compliant RADNER Reading Charts printed in Times New Roman PS and Arial MS. Print sizes were equalised in terms of x-heights. The reading charts were presented in random order at a test distance of 40 cm. Three reading acuity (RA) parameters were investigated: RA, reading acuity score (RAS) and critical print size (CPS); as well as three reading speed parameters: mean reading speed for all sentences (MEAN-ALL RS), mean reading speed within the range of 0.8–0.3 logRAD (MEAN-RS) and maximum reading speed (MAX-RS). Results No statistically significant differences were found between Times New Roman PS and Arial MS for any of the three reading acuity-related parameters (RA, RAS and CPS) or any of the three reading speed-related parameters (MEAN-ALL RS, MEAN-RS and MAX-RS) (all p > 0.07 for acuity-related parameters, and all p > 0.40 for reading speed-related parameters). The differences in all reading parameters were small, with narrow confidence intervals. There were strong correlations between the two fonts, with correlation coefficients ranging from r = 0.76 to 0.89. Conclusion When equalised for x-height and layout, the comparable reading performance observed with Times New Roman PS and Arial MS suggests that these fonts can be used interchangeably for reading charts standardised in accordance with ISO 7921:2024.