Eye Movements and Reading

When we read, we have the impression that our eyes glide smoothly across the page. However, this is an illusion. The eyes stay relatively fixed for about 200 to 300 milliseconds (ms) and then quickly jump (in about 20–30 ms) to a new location. The stable periods are called fixations and the eye movements are called saccades. Vision is suppressed during saccades (to prevent the perception of blur during eye movements) and useful information is obtained only during fixations. Our eyes typically move forward through the text, although regressions (saccades going backward through the text) account for about 10 to 15% of the movements. When readers come to the end of a line, a large leftward eye movement (called a return sweep) is made to ...