Patent ID: 6190374
Filing Date: 2001-02-20
Classification: A61F

Abstract:
A system for operating upon a cornea for delivering a laser beam having a wavelength in an ultraviolet range emitted from a laser light source to the cornea, and for correcting ametropia by ablating the cornea with said laser beam, the system comprising:a correcting optical subsystem including:a moveable aperture which can be positioned so that the center of the moveable aperture can be located at a corneal center when correcting hypermetropia, and which can be positioned so that the center of the moveable aperture is located at a shifted position below the corneal center, such that an opening of said moveable aperture is located at an area including a lower peripheral part of the cornea including an optical part and a non-optical part of the cornea, when correcting presbyopia; anda beam-rotator for causing the laser beam shifted from an optical axis of said correcting optical subsystem to rotate about said optical axis;wherein said correcting optical subsystem ablates more at the periphery of the cornea than at the center of the cornea when correcting hypermetropia, and said correcting optical subsystem ablates at least the lower peripheral part of the optical part of the cornea as a near-point portion when correcting presbyopia;input means for inputting information necessary for defining a corneal shape after ablation;determining means for determining the corneal shape based on the information inputted by said input means, and for obtaining an ablation amount of a part of the cornea; andcontrolling means for controlling said laser light source and said correcting optical subsystem;wherein said laser light source and said correcting optical subsystem are driven such that said cornea has double focal points upon correction of presbyopia.