Validation of the MNREAD–Portuguese Continuous–Text Reading–Acuity Chart

Abstract

Abstract: : Purpose: The MNREAD Acuity Charts are continuous–text reading–acuity charts that were developed at the Minnesota Laboratory for Low–Vision Research at the University of Minnesota. These charts are used to measure reading speed as a function of logMAR print size for normal and low–vision patients. The test provides estimates of reading acuity, critical print size and maximum reading speed. The purpose of this study was to validate the recently developed MNREAD–Portuguese chart (MNREAD–P), which was designed to provide equivalent information about reading–acuity for Brazilian Portuguese speakers. We asked: 1) does MNREAD–P produce the same pattern of results as the original MNREAD, and 2) is the estimate of reading speed from MNREAD–P a valid predictor of real–world reading speed? Methods: Twenty subjects with normal vision (20/20 or better, with best refractive correction) were tested on MNREAD–P, yielding plots of reading speed vs. print size from 1.3 logMAR to the minimum size that could be read, in 0.1 logMAR steps. Several curve–fitting methods were examined, including the bilinear fit often used for the English version of MNREAD. Subjects also read a Brazilian newspaper article (print size = 0.6 logMAR) containing 92 words, and reading speed was recorded. Results: The bilinear fit (a two–phase linear–flat least squares fit) provides a good characterization of MNREAD–P data, thereby permitting estimates of reading acuity, critical print size and maximum reading speed. In other words, the MNREAD–P produces the same pattern of results as the original MNREAD. Furthermore, estimates of maximum reading speed are statistically equivalent to measures of reading speed taken from passage reading. The correlation between the MNREAD–P and passage reading was significant at r = 0.82. Conclusions: The MNREAD–P produces the same pattern of results as the original MNREAD. Reading speed from the MNREAD–P is a good predictor of reading speed in normal Portuguese text reading.

Keywords: reading • visual acuity