A NEW GERMAN READING CHART FOR THE SIMULTANEOUS EVALUATION OF READINGACUITY AND READING SPEED

Background Reading acuity as well as reading speed are good predictors of everyday visual function. As visual acuity tests are poor predicto rs of the real-world function, performance-based tests, e.g. reading s peed measurements, can be used for the determination of visual functio n. Thus, a German reading chart was developed in order to evaluate rea ding acuity as well as reading speed. Methods Print size is defined as the height of a lower case x and progresses logarithmically from one phrase to another (factor: 1.25). Reading acuity is determined in LogR AD (Reading Acuity Determination). 32 short German phrases were create d, comparable concerning grammatical difficulty as well as in number ( n=14), length and position of words. The reading speed parameters meas ured with a stop-watch in 160 persons (aged: (empty set = 21a +/- 3.8a ) were calculated in words per minute (w/min). Out of the 32 phrases t he 24 most similar ones were selected statistically and used for the r eading charts (Radner Reading Charts). With these reading charts a rea ding acuity score (LogRAD-score) can be calculated considering reading errors in words of different length. Reading speed can be determined at the same time. Reading acuity (LogRAD-Score) was measured in 32 nor mal eyes of 16 students and compared to the angular visual acuity (Log MAR). Results The mean reading speed of the test persons was 211.8+/-3 4.1 w/min. 24 phrases fulfilled the test item criteria for the reading chart: mean +/- 0.25 x SD. The reliability analyses yielded an overal l Cronbach's alpha coefficient of 0.9&! The mean visual acuity measure d in 32 eyes was - 0.115 +/- 0.097 LogMAR and the mean reading acuity score was +0.026 +/- 0,091 LogRAD. The mean difference was + 0.104 +/- 0.066 and the correlation between LogMAR and LogRAD was good (r = 0.5 9). Conclusions With these reading charts it is for the first time pos sible to simultaneously determine reading acuity as well as reading sp eed in German. The high reliability of the 24 phrases and the high cor relation between LogMAR and LogRAD leads us to expect a good reproduci bility of the reading acuity evaluations. For the ''Radner Reading Cha rts'' we have shown that print size is the main reason for changes of reading speed.