Purpose To add a new set of 24 sentence optotypes to the German version of the RADNER reading charts and to investigate whether sentences constructed based upon an optimised concept of sentence optotypes can be used together with the original 38 sentences.
Methods Twenty-eight optimised sentence optotypes were constructed based upon the concept of sentence optotypes as established for the RADNER Reading Charts, with words having the same number of characters and syllables being placed in the same positions. The best comparable sentences were statistically selected in 30 volunteers. Reading speed and the number of errors were determined. Validity was analysed in comparison to a 111-word long standardised paragraph and 7 of the 38 original sentence optotypes.
Results The mean reading speed obtained with the 28 sentences was 192.30±26.69 words per minute (wpm), as compared with 192.47±25.32 wpm for the 7 original sentence optotypes and 165.28±20.82 wpm for the long paragraph; 24 of the 28 optimised sentences met our selection criteria for reading speed/time (mean reading speed: 192.41±26.58). The mean number of reading errors was 0.10±0.30. The correlation between the 24 optimised sentence optotypes and the long paragraph was r=0.90. Reliability analyses yielded an overall Cronbach's α coefficient of 0.992.
Conclusion The 24 new sentence optotypes can be integrated into the existing set of 38 original sentences. Since all the statistical results obtained were similar to those of the original sentences, the best possible reliability had apparently already been achieved with the original sentence optotypes.
- Optics and Refraction
- Visual perception
- Visual (cerebral) Cortex
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Contributors WR who serves as the corresponding author, provided substantial contributions to the conception of the work, the design of the work as well as the acquisition, analysis or interpretation of data for the work. WR, SR, GD were involved in drafting the work, and revising it critically for important intellectual content; finally approved the version to be published; and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. SR provided substantial contributions to the conception of the work, the design of the work as well as the acquisition, analysis and interpretation of data for the work. GD provided substantial contributions to the conception and design of the work as well as analysis and interpretation of data for the work.
Competing interests WR receives royalties for the RADNER reading charts, of which seven optotypes were used. All other named authors have no affiliation with or involvement in any organisation or entity with any financial interest in the subject matter or materials discussed in this manuscript.
Provenance and peer review Not commissioned; externally peer reviewed.
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