| 摘要 |
The invention contemplates controlled ablation of the cornea (60), using ultraviolet laser radiation, wherein irradiated flux density and exposure time are so controlled as to achieve desired depth of the ablation. Sculpturing action for corneal curvature correction results from controlled change of projected laser-spot size in the course of a given treatment, and for promoting regrowth of the epithelium, sculpturing is effected so as to avoid the formation of sharp discontinuities in the corneal profile. Thus, for hyperopia correction where prior sculpturing techniques would have produced a sharp discontinuity in corneal profile at the juncture of operative and non-operative regions, the invention proposes to sculpt a profile smoothing annulus around the operative area (61) thereby to encourage epithelial regrowth. |
