[Development and validation of the MNREAD reading acuity chart in Portuguese]

To create and to validate a version of the Minnesota Low Vision Reading Test (MNREAD) acuity chart for the Portuguese language.

The Minnesota Low Vision Reading Test acuity chart contain 19 sentences (logMAR 0.5 to 1.3) with 60 characters printed on three lines. All the sentences must have the same length with simple vocabulary. A total of 110 sentences were generated. The sentences were presented to 36 subjects (20 adults and 16 children) and mistakes and reading time were marked. 38 sentences were selected for a prototype (MNREAD-P). Sentences with extreme high and low mean reading time, large standard deviation, and with persistent mistakes by subjects were excluded.

Twenty subjects with normal vision (logMAR 0 or 20/20 or better, with best refractive correction) were tested with the MNREAD-P and read a passage of text, representing normal, day-to-day reading. Reading speeds in words per minute were recorded for both the MNREAD and the text passage.

Sentences in the MNREAD Portuguese chart are sufficiently consistent to provide reliable measures of reading abilities. Reading speeds for the passage (logMar = 0.6) were 197.8 words/minute and the maximum reading speeds calculated by the MNREAD-P were 200.1 words/minute. The correlation between the two measures was r = 0.82.

The MNREAD-P was tested on normal vision subjects and the results were the same from the original Minnesota Low Vision Reading Test. The reading speed measured on the MNREAD-P was statistically equivalent to the reading speed of the passage.