Patent ID: 8758331

Claim:
A system for refractive surgical treatment of corneal tissue, said system including: a pulse laser capable of producing a succession of spatially overlapping, successive laser beam pulses under the control of a control system onto a portion of target corneal tissue, wherein each laser pulse applied to said portion of corneal tissue exhibits an energy that is less than the laser pulse energy which is required for producing material division with an isolated laser pulse of said portion of corneal tissue but which irradiates said portion of corneal tissue with a sufficient total energy to effect material division when a target location of said corneal tissue is spatially overlapped with laser pulses by 10-100%, an optical system with a numerical aperture that controls focus of laser beam pulses from said pulse laser on a division region of said portion of said corneal tissue, and a control system configured to controllably adjust two or more of: (a) laser pulse energy, (b) the laser pulse intensity, (c) the size of focus area, (d) pulse duration of individual laser pulses, (e) laser pulse repetition frequency, and (f) the relative advance speed between laser beam pulse exposure area and said corneal tissue, and configured to apply to said corneal tissue an energy per pulse that is less than the laser pulse energy which is required for producing material division with an isolated laser pulse but which irradiates said corneal tissue with a sufficient total energy within the thermal relaxation time of said tissue to effect material division while said corneal tissue is spatially overlapped with laser pulses by 10-100%.