Figure 8

Gaze direction measurements. Measured horizontal gaze direction (deg; mean ± SD) as a function of presented horizontal position (deg) for the PowerRefractor and PowerRef II. Regression equations are shown separately. As indicated by the slope of the regression equations, the distance between the presented horizontal positions was underestimated by the measured gaze direction, even though the measurement distance of 1 m was correctly maintained; maybe the Hirschberg ratio set by the default routine was to low for our sample.