Development and Validation of the Persian Version of the MNREAD Acuity Chart

To develop the Persian version of MNREAD acuity charts and test their repeatability in a normal adult population.

Two hundred sentences were constructed using the most frequent words of 8-year-olds schoolbooks. The number of characters and sentence length were adjusted based on the design principles of the Minnesota Low Vision Reading Test. Two Persian language teachers checked the sentences for syntax and meaning. The accepted sentences were read by 20 adults and then by 20 children. Using RADNER charts method, the sentences with inappropriate reading time and repeated errors were excluded. Thirty-eight sentences were approved to create charts. To check the charts' validity and repeatability, 20 adults read both charts and a paragraph of a daily newspaper. Reading acuity, critical print size, and maximum reading speed were calculated. The measured reading speeds were compared to the readers' reading speeds for a paragraph of a daily newspaper. Bland-Altman plots were used to evaluate the agreement between the two charts.

Thirty-eight selected sentences were used in the final printed charts. There were significant correlations between maximum reading speed for Charts 1 and 2 (r = 0.87, P < 0.0001), Chart 1 and newspaper paragraph (r = 0.73, P = 0.001), and Chart 2 and newspaper paragraph (r = 0.83, P = 0.0001). Correlations were observed between reading acuities and critical print sizes of two charts (r = 0.72, P < 0.002 and r = 0.77, P = 0.00). The 95% limits of agreement in reading acuity, critical print size, and reading speed between Charts 1 and 2 were ± 0.034 logMAR, ±0.11 logMAR, and ±8.00 words per minute, respectively.

The designed Persian MNREAD charts are repeatable and could be used reliably to calculate near acuity, reading speed, and critical print size in Persian-speaking people.