Before we go deeper into R.A.D.A.R. Method, lets introduce some helpful definitions.
- Fixation: is the maintaining of the visual gaze on a single location. On average, fixations last for around 200 ms during the reading of linguistic text, and 350 ms during the viewing of a scene.
- Saccades: are quick, simultaneous movements of both eyes in the same direction.
- Reading path: is the resulting series of fixations and saccades.
- Visual acuity: it describes the acuteness or “sharpness” of vision; that is the ability to perceive small details.
- Regressions: is a backward movement of the eye when reading a line of text- good readers do it less than weaker readers, who go back to check things more frequently.
The reading path of a normal reader (left) and a dyslexic reader (right). Blue circles are the fixations and the orange lines are the saccades. The bigger the circle, the longer the fixation duration.