Differences in occurrence interval and accuracy between visually triggered saccade and internally guided saccade

The differences in the characteristics of visually triggered saccade and internally guided saccade are investigated using the fixed target saccadic test (FTST) and the opposite target saccadic test (OTST). It is found that visually triggered saccade is fast in peak velocity and short in duration compared to internally guided saccade. The former needs a refractory period while the latter does not always. The accuracy of the visually triggered saccade depends much more on the target eccentricity in accuracy than that of internally guided saccade.<>