A system and method for taking non-invasive blood pressure and other vascular parameter measurements includes placing a vascular compression device about an appendage of a subject. At a point in the access line, a photometric measurement is conducted of the change in hematocrit with respect to time. Furthermore, keratometric andor pachymetric measurements can also be carried out. The plurality of domes each have a top, a base and a side extending from the top to the base at an angle of divergence exceeding 10\xb0. The control unit is coupled to the buffer unit, and used to generate a control signal to the buffer unit. Thus, a line between the first and second working heads is directed through the centers of initial apertures in the annular work piece, one after another, to facilitate precise processing of sections of the annular work piece corresponding to the initial apertures.