The Rx Point Distance tool is a special ruler in the Planar Dosimetry Window which displays a vector and its length between a location of interest and the current Rx point (e.g. the radial distance from the inner sclera through the Rx point in the direction of the eye origin). The ruler is only visible if its vector lies entirely in the plane being plotted. The tool is enabled by default and may be hidden by deselecting Rx Point Distance from either the contextual menu attached to the Rulers button or from the Plot Options Menu.
The Rx Point Distance tool may be customized using the Rx Point Properties sheet which is accessed from the contextual menu of the Planar Dosimetry Window Rulers button or by double clicking the center of the label on the Rx distance vector. In this properties sheet you can select one of several predefined locations or one of the 16 user defined points of interest (POI). The label position slider affects the location of the label along the vector. The default is midway along the vector. Move the the label position slider fully to the left to hide the label. You may also elect to display this vector in the 3D Setup Window by enabling the Show 3D checkbox control.