Learning to read consists of learning to master all the partial tasks necessary for reading individually and in their coordinated sequence.

The resulting reading flow depends on the learning progress of the child and the text to be read and is also individually different for experienced readers, similar to running step lengths, step positions and step frequency depend on both the individual runner and the terrain. During the reading process, the child decides from fixation phase to fixation phase how large the word segment to be read should be. If it tries to read too large word segments, the recognition process fails and reading errors occur. If the child selects word segments that are too small, reading errors do not occur, but reading progresses unnecessarily slowly, since the child could also reliably recognize larger word segments. In order to ensure error-free and fluent reading, the eye jump size must therefore be adapted to the length of the word segment perceptible and recognizable by a person. During the reading process, the child also decides on the duration of a fixation phase.
Trouble-free reading also depends on whether the fixation time is sufficient to perceive the word segment to be read precisely enough during this fixation phase and to retrieve the corresponding sound sequence and meanings from memory.
Experience has shown that a considerable number of children who learn to read with the help of today’s methods suffer from noticeable and sometimes serious reading disorders. There are many reasons for such reading disorders. It goes without saying that the first requirement is sufficient vision so that the text to be read can be recognised with sufficient accuracy, and that pronounced eye movement disorders can be ruled out. However, such disorders can easily be diagnosed in an ophthalmological or neurological examination and cannot be corrected in reading classes.
Much more problematic are those disorders which have deeper causes and are not so easily detectable, but which result in persistent, pronounced reading weaknesses. In these cases an individual diagnosis is indicated. It must first be determined whether the reading disorder is caused by a disturbed individual performance which could not be compensated by another performance or whether there is a lack of coordination between undisturbed individual performances.
Such “adaptation disorders” are particularly frequent and can have a variety of causes. A differentiated diagnosis of reading disorders must recognize whether such a lack of adaptation exists and what the causes are. To this end, it must first be investigated which word segments a person can perceive and recognise at all “at once” within a fixation phase and how much time is required for this. In addition, the size of a person’s gaze jumps during reading must be examined. Only when these individual achievements are known can it be assessed whether the aforementioned “adaptation disorder” is a possible cause of the reading disorder.