Purchase this article with an account.
Aurelie Calabrese, Safa Gamam, J. Stephen Mansfield, Gordon E Legge; Implementing the MNREAD Reading Acuity Test on an iPad3. Invest. Ophthalmol. Vis. Sci. 2014;55(13):5601.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The MNREAD ACUITY CHARTS are continuous-text reading-acuity charts suitable for measuring the reading performance of people with normal and low-vision. MNREAD measures three parameters of reading: 1) Reading Acuity ; 2) Critical Print Size ; 3) Maximum Reading Speed. We have recently implemented the English version of MNREAD on an iPad3. The pixel resolution and screen size of the iPad allow only 14 steps in print size to be displayed, compared with 19 steps on the chart. But the iPad can be used at different viewing distance to increase the effective range of angular print sizes. To assess the equivalence between printed chart and iPad versions of MNREAD, we focused on two questions: 1) Do the chart and iPad versions yield similar estimates for the three parameters of reading? 2) Does the iPad version provide equivalent estimates of the three reading parameters when tested at different viewing distances?
Digital versions of the MNREAD charts were created and stored as pdf documents, with one sentence centered on each page. Font, print size, interline and word spacing exactly matched the printed charts. Normally sighted subjects (N=46; age 18 to 44) were tested on the iPad at viewing distances of 20, 40, 80 & 160cm, and on the charts at 40 & 160cm. Sentences were presented one at a time on the iPad using the iBooks app. The experimenter triggered each sentence by clicking on the screen, timed the reader with a stopwatch, and recorded errors. Data were plotted on MNREAD score sheets yielding curves of reading speed vs. print size. These curves were used to estimate the three reading parameters. Mixed-effects models were used to estimate the effect of: 1) version and 2) viewing distance on each parameter.
Reading acuity and critical print size were not significantly different between the chart and the iPad. Maximum reading speed was slightly but significantly faster (6wpm-3%) with the printed chart (p<0.001). For both versions, the values of the three parameters did not differ significantly across the range of viewing distances.
The digital version of MNREAD on an iPad3 yields similar results to the chart version of the test. The restricted range of print sizes available on the iPad3 can be compensated for by varying viewing distance. Preliminary results from ongoing measurements with low-vision subjects also show equivalent results on the iPad3 and chart versions of the test.
This PDF is available to Subscribers Only