Method and apparatus for removing cataractous lens tissue by laser radiation

Apparatus for surgical, non-invasive destruction of cataracted natural-lens tissue within an afflicted eye, comprising

• viewing means having an optical objective on a viewing axis adapted for alignment with the afflicted eye,
• a laser and optical means for treating the beam output of said laser to translate said output into a conical ray bundle convergent to a focal spot of maximum power density, said optical means including an axially movable element for providing Z-axis displacement of said focal spot,
• a visible-light source and means including at least said movable element for translating visible-light output of said source into at least part of the conical-ray bundle convergent to said focal spot,
• two-component scanning means interposed in said convergent-ray bundle for scan deflection of said focal spot in directions normal to the X-axis, said scanning means and said optical means being so positioned as to place said focal spot at the cataracted lens with the viewing axis normal to the center of the field of two-component scan, said scanning means being adapted in a first selected mode for selective manipulation of displacement in each of the two component actions thereof, and said scanning means being adapted in a second selected mode for automated scan displacement of said focal spot under computer control and within said field,
• whereby in said first mode and using the visible-light output of said source, said focal spot may be selectively and adjustably progressed in a visually observed path of displacement to develop a closed perimeter of desired limiting laser action on the cataracted lens,
• computer means including a data-storage device and means for entering therein coordinate data for the observed development of said closed perimeter, said computer means including a program for control of the component actions of said scanning means as limited by said closed-perimeter data, and
• selectively variable means associated with said computer means for selectively and differently limiting the field area of programmed scanning, within said closed perimeter, for each of a plurality of Z-axis displaced positions of said focal spot.

A method of surgical, non-invasive destruction of cataracted natural lens tissue within an afflicted eye, said method comprising

• (a) optically treating the beam output of a laser such that said beam output is translated into a conically convergent ray bundle to a focal spot of maximum power density,
• (b) orienting said ray bundle to focus on said lens tissue via transmission through the cornea of the eye, whereby said maximum power density is focused at the lens tissue but the cornea and retina of the eye are exposed to relatively diffused and substantially reduced power density,
• (c) exciting the laser to induce ablative photodecomposition and/or thermal decomposition and/or photofragmentation and/or photoemulsification via said maximum power density but at a level such that said diffused power density does not induce decomposition of tissue other than at the cataracted lens tissue, and
• (d) scanning the cataracted lens tissue with said focal spot and within a predetermined limiting perimeter until ablative photodecomposition and/or thermal decomposition and/or photofragmentation and/or photoemulsification is substantially complete within said perimeter.