Patent ID: 6585723
Filing Date: 2003-07-01
Classification: A61B,A61F

Abstract:
A corneal surgery apparatus which ablates corneal tissue with a laser beam, the apparatus comprising:a patient positioning unit on which a patient is placed on his back so that his eye faces upward; an irradiation unit including a light directing optical system for directing the laser beam to an intended range of a cornea of the patient's upward-facing eye, wherein the laser beam has a wavelength in a far ultra-violet region and an intensity capable of causing ablation to the irradiated corneal tissue; a corneal shape measurement unit which measures a three-dimensional shape of the upward-facing cornea, the corneal shape measurement unit including: a measurement light projecting optical system, including a first pinhole plate, for projecting a measurement light onto the upward-facing cornea, wherein a convergent point of the measurement light is shifted from an anterior surface of the cornea to a posterior surface of the cornea by moving a focusing lens along a central optical axis of the measurement light projecting optical system; wherein the central optical axis of the measurement light projecting optical system is made to be coaxial with a central optical axis of the light directing optical system midway on an optical path; a measurement light receiving optical system, including a second pinhole plate placed at a position conjugate with the first pinhole plate with respect to the cornea and a photo-detector for receiving reflected measurement light from the upward-facing cornea having passed through the second pinhole plate; wherein a central optical axis of the measurement light receiving optical system is divided from the central optical axis of the light directing optical system midway on an optical path; a scanning unit which scans a projection spot of the measurement light on the upward-facing cornea in XY directions; an arithmetic unit which performs arithmetic to obtain three-dimensional shapes of the anterior and posterior surfaces of the upward-facing cornea based on a position of the projection spot in the XY directions, a result detected by the photo-detector and a position to which the focusing lens is moved, and to obtain a thickness of the upward-facing cornea based on the obtained three-dimensional shapes of the anterior and posterior surfaces of the cornea; and a monitor unit which monitors a relationship between corneal ablation data and data about the thickness of the upward-facing cornea obtained by the corneal shape measurement unit.