Abstract: A device for determining biometric variables of the eye, as are incorporated in the calculation of intraocular lenses including a multi-point keratometer and an OCT arrangement. The keratometer measurement points are illuminated telecentrically and detected telecentrically and the OCT arrangement is designed as a laterally scanning swept-source system with a detection region detecting the whole eye over the whole axial length thereof. Illumination points are arranged in three rings concentrically around an instrument axis; and the three rings include a first ring, a second ring and a third ring and the illumination points on the first ring and the third ring are rotated in relation to the illumination points on the second ring such that each of the illumination points on the first ring is on a common radial with one of the illumination points on the third ring and each of the illumination points on the second ring is not on the common radial.

Abstract: For the correction of measurement errors, due to vibration, of coordinate measuring devices, the time course of the interfering vibrations is stored by means of sensors (a.sub.x, a.sub.y, a.sub.z) on a vibrating portion of the coordinate measuring device. The measured values of the sensors are adjusted with previously determined and stored correction parameters, which describe the natural frequency (.nu.) and the damping constants (.delta.) of the vibrations and also the amplitude and phase information of the characteristic modes (G.sub.r) of the vibrations contributing to the interfering vibrations. The measurement errors, due to vibration, of the coordinate measuring device at the instant of probing are then calculated from the time course of the corrected measurement values of the sensors (a.sub.x, a.sub.y, a.sub.z).

Abstract: A computer-operated coordinate-measurement machine has two length-measurement systems arranged in parallel for measuring the longitudinal displacement of a probe carried by the portal (3-5) of the machine, and these two length-measurement systems (13, 14) may belong to different precision classes. A computer-associated device (16) forms an absolute position-measurement value (Ym) from length-measurement signals of the more precise measurement system (13) and said device forms a dynamic measurement or instantaneous deviation value (Ys-Ym) from the difference between length-measurement signals of the respective systems (13, 14). The computer of the machine calculates the effective instantaneous position (Ym+.DELTA.y) of the probe (9a, b, c) borne by the portal (3-5), using the instantaneous value of the transverse position of the probe on the portal, in conjunction with the absolute measurement value (Ym) and the dynamic measurement value (Ys-Ym).