The repeatability of MNREAD acuity charts and variability at different test distances.

PURPOSE

The purposes of this study are to establish the repeatability of the MNREAD acuity charts in a normal adult population and to determine the coefficient of repeatability for reading acuity, reading speed, and critical print size. The study also investigates how changing the working distance affects these parameters.

METHODS

Thirty normal young adults (mean age, 23.3 years) participated. Test-retest repeatability was assessed at 40 cm over two sessions by the same examiner using MNREAD charts 1 and 2. Additional measurements were also carried out at 24 cm and 52 cm working distances. The distance and the version of the chart used were randomized.

RESULTS

The coefficient of repeatability was found to be +/- 0.05 logarithm of the minimum angle of resolution (logMAR) for reading acuity, +/- 0.12 logMAR for critical print size, and +/- 8.6 words per minute for reading speed. Reading acuity and critical print size changed significantly with testing distance (p = 0.001). No changes were found in the reading speed at the different test distances (p = 0.27).

CONCLUSIONS

The MNREAD acuity charts can be used reliably to measure reading acuity, reading speed, and critical print size in a normal adult population.