Method and apparatus for removing cataractous lens tissue by laser radiation

Claim 2

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 Z-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 variable means associated with said computer means for effecting predetermined shrinkage of the field area of programmed scanning, within said closed perimeter and as a function of Z-axis displacement of said focal spot.

Claim 3

Apparatus according to claim 1, in which said two-component scanning means is of the orthogonally related X-Y variety.

Claim 4

Apparatus according to claim 1, in which said two-component scanning means is of the polar R-θ variety.

Claim 5

Apparatus according to claim 1, in which said variable means is computer controlled for initial scan of a predetermined most-reduced central area within said perimeter for a first Z-axis position selected to place said focal spot at the anterior surface of the cataracted lens, and in which said variable means is computer controlled for a subsequent scan of a less-reduced central area within said perimeter for a subsequent Z-axis position selected to place said focal spot at a posteriorly indexed position within the cataracted lens.

Claim 6

Apparatus according to claim 1, in which said viewing means is a stereo microscope.

Claim 7

Apparatus according to claim 5, in which said microscope includes a local light source and optical means for illuminating the field of scanning with light from said local source.

Claim 8

Apparatus according to claim 1, in which said variable means includes selectively variable means for adjustably positioning, within said closed perimeter, a shrunken field area of programmed scanning, whereby as an operator notes by local color change that cataracted lens tissue has been removed at least to the depth of the posterior capsule, said operator may reduce and shift the scanned local region to avoid further laser action at the region of local color change.

Claim 9

Apparatus according to claim 1, in which said computer means further includes means for entering in said data-storage device the coordinate data for the observed development of a second and more locally closed perimeter defined by an operator who has noted by local color change that cataracted lens tissue has been removed at least to the depth of the posterior capsule, the more locally closed perimeter being as developed by observation of the focal spot of visible light in a first-mode operation of said scanning means following a period of laser operation and second-mode scanning, said computer means being programmed for two-dimensional scan action without incursion into the area of said second and more locally closed perimeter.

Claim 10

Apparatus according to claim 8, in which a shutter is included in the beam output of said laser and in which said shutter is computer-controlled to preclude laser-output focus at the focal spot during periods of scanner deflection of the spot through the more locally enclosed perimeter.

Claim 11

The apparatus according to claim 1, in which the laser is pulsed laser wherein the energy of individual pulses is from about 1 to about 30 millijoules.

Claim 12

The apparatus according to claim 10, in which the convergent ray bundle has an included angle in the range of about 16 to about 20 degrees at entrance to the cornea of the eye.

Claim 13

The apparatus according to claim 10, in which the laser is of the neodymium-YAG variety.

Claim 14

The apparatus according to claim 1, in which the laser is of a variety characterized by emission in the ultraviolet.

Claim 15

The apparatus according to claim 1, in which the laser is an excimer laser.

Claim 16

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.

Claim 17

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.

Claim 20

The method of claim 16, in which the iris of the eye is dilated and said perimeter is within the inner confines of the dilated iris.

Claim 21

The method of claim 16, in which the convergent ray bundle has an included angle in the range of about 15 to about 30 degrees at entrance to the cornea of the eye.

Claim 22

The method of claim 16, in which first scanning is limited to a first and relatively small central area within said perimeter, and in which the focal spot is successively advanced in increments of depth into the lens tissue for each succeeding scan of a progressively larger centered area within said perimeter.

Claim 23

The method of claim 19, in which, after progressively larger scans have reached a scan of the area bounded by said perimeter, the focal spot is successively advanced in increments of depth into the lens tissue for each succeeding scan of a progressively smaller centered area within said perimeter.

Claim 24

The method of claim 16, in which an irrigation/aspiration procedure is performed with an isotonic solution in the anterior chamber of the eye throughout the period of laser excitation.

Claim 25

The method according to claim 16, in which the laser is of a variety characterized by emission in the ultraviolet.

Claim 26

The method according to claim 22, in which the laser is an excimer laser.