Operation apparatus for correcting ametropia with laser beam

An apparatus for use in ablating a cornea of an eye by a laser beam emitted from a laser source and passed along an optical path onto the cornea to correct ametropia of the eye, comprising:

• a diaphragm with a variable diameter aperture disposed in the optical path along which the laser beam is passed onto the cornea;
• a movable shading means disposed in the optical path for shading a central portion of the aperture of the diaphragm extending along a meridian diameter of the aperture and varying a width of the shaded area of the aperture when moved;
• control means connected to the diaphragm and the shading means for controlling the aperture diameter and moving the shading means to vary the width of the shaded area and thereby form a laser beam image comprising two laser beam portions separated by the shaded area;
• an image rotator disposed between the diaphragm and the cornea of the eye for rotating the resulting laser beam image about the optical path and on the cornea;
• and
• means for controlling the image rotator to rotate the laser beam image on the cornea so that the depth of an area of the cornea ablated by the laser beam is substantially uniform in the laser beam rotating direction when the image rotator has rotated the laser beam image 360.degree.;
• whereby the cornea can be ablated more at its periphery than at its center so as to correct hypermetropia.