| 摘要 |
PURPOSE:To achieve a correction of astigmatism and near sight-by one operation by limiting an irradiation area of laser to ellipse and changing the size of the diameter in the irradiation area while the direction of the major diametrical line of the ellipse is moved relative to an eye to be operated. CONSTITUTION:A laser beam from an excimer laser light beam 1 is deflected by 90 deg. each sequentially with a number of flat mirrors 2 and 3 and 6. An abrasion area is limited with an aperture 4 which turns about the Z axis (optical axis) and allows the altering of an angle with respect to an optical axis centered on an Xa axis while enabling the altering of an opening diameter. Moreover, the aperture 4 is projected onto an eyeball cornea 7 with a projection lens 5. When an angle at which the aperture 4 is inclined in centering on the Xa axis is set to theta, the size of the laser beam passing through the aperture 4 reduces in the Ya axis as the angle theta increases. The cornea is excised in a shape of a toric lens thereby enabling the correction of near sight and astigmatism simultaneously. |
