Method and apparatus for obtaining irradiation intensity of a laser beam, and apparatus for irradiating the laser beam

An apparatus for ablating a cornea of a patient's eye by irradiation of an ultraviolet laser beam onto the cornea, the apparatus comprising:

• irradiation means having a laser source for emitting the laser beam and an irradiation optical system for irradiating the laser beam emitted from the laser source onto the cornea;
• an observation optical system having an objective lens, for observing the patient's eye;
• input means for inputting corneal ablation data for ablating the cornea into a desired corrected shape;
• calculation means for obtaining corneal ablation control data for the irradiation means based on the inputted corneal ablation data;
• a fluorescent glass for calibration including a glass component and a rare-earth component, the fluorescent glass being disposed in an optical path of the irradiation optical system;
• a fluorescence detecting optical system having an area sensor having a sensitivity to fluorescence, for obtaining an intensity distribution of the fluorescence emitted from the fluorescent glass by irradiation of the laser beam onto the fluorescent glass, the fluorescence detecting optical system detecting the fluorescence passed through the objective lens;
• mode setting means for setting a calibration mode in which the irradiation means is controlled to ablate a predetermined ablation area at a constant ablation depth so as to calibrate variation of irradiation intensity distribution of the laser beam;
• and
• calibration means, when the calibration mode is set and the laser beam is irradiated by the irradiation means controlled to ablate the predetermined ablation area at the constant ablation depth, for calibrating at least one of the corneal ablation data and the corneal ablation control data based on the intensity distribution of the fluorescence obtained by the fluorescence detecting optical system.