Corneal surgery apparatus

A corneal surgery apparatus, which comprises:

• a laser irradiation optical system capable of changing an irradiation position with a laser beam emitted from a laser source on a cornea of a patient's eye;
• and
• an eye position change detection unit, which includes:
• an illumination optical system arranged to illuminate an anterior-segment of the patient's eye with infrared illumination light;
• and
• an image pick-up camera arranged to pick up an image of the anterior-segment illuminated by the illumination optical system, and is arranged to detect change in eye position including torsion of an eyeball of the patient's eye subjected to a surgical operation based on an iris pattern in the anterior-segment image picked up with the image pick-up camera, and is arranged such that the irradiation position with the laser beam which is applied by the laser irradiation optical system tracks movement of the patient's eye based on a result of the detection by the eye position change detection unit, and the cornea is ablated to a desired shape by the application of the laser beam,
• wherein the corneal surgery apparatus further comprises a control unit arranged to extract the iris pattern at an iris portion and a background of the iris pattern based on luminance information on the anterior-segment image picked up with the image pick-up camera, and adjust at least one of a set value of an illumination light amount of the illumination optical system and a set value of a gain of the image pick-up camera so that a luminance difference between the iris pattern and the background of the iris pattern is maximized or exceeds a predetermined reference value, and luminance at the iris pattern at the iris portion and the background of the iris pattern is not saturated;
• a projection optical system arranged to project a visible light beam onto the patient's eye;
• a setting unit arranged to set an allowable range of variation of a pupil size such that the iris pattern is detectable, the iris pattern being used as a reference for tracking the patient's eye;
• and
• a light-amount adjustment unit arranged to determine whether or not the pupil size detected by the eye position detection unit goes beyond the allowable range during the surgical operation, and automatically adjust the light amount of the projection optical system based on a result of the determination.