Where do the eyes fixate within a line of text, within words, and relative to each other?

We recorded binocular eye movements of adult readers as they read single German sentences. Readers frequently fixate above or below the actual line of text, but the preferred vertical viewing location is within the upper and lower sentence boundaries. Fixations above and below the line of text lead to prolonged fixation durations. The effect is likely to result from visual acuity limitations, modulated by cognitive-attentional factors. Furthermore, analyses of horizontal and vertical eye disparities indicate that the most prevalent type of disparate fixation is crossed (i.e., the left eye is located further to the right than the right eye) while the left eye frequently fixates somewhat above the right eye. At the end of fixation, horizontal disparities are reduced, yet the two eyes frequently fixate at different letters within a word, sometimes even at different words. Implications for our understanding of eye-movement control in reading are discussed.