System and Method for Photoablation Using Multiple Focal Points with Rotating Beam Splitter
AssigneeTechnolas Perfect Vision GmbH
InventorJosef Bille
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Abstract
A system and method for performing ophthalmic surgery requires splitting a laser beam into a pattern having a plurality of focal points. The pattern is then moved along a spiral path according to a predetermined, two-phase protocol. In the first phase, a radial spacing “Δr” between spiral lines, and the velocity of the pattern “rω” are held constant as the radius “r” is decreased from r1 to r2. In the second phase the angular velocity “ω” is held constant and the radial spacing “Δr” is proportionally increased as “r” is further decreased from r2 to r3. Additional LIOB is required both inside r3, as r is reduced to zero and, then, along the periphery of the treatment area for a rim cut at r1.
Claims20
A system for performing ophthalmic laser surgery which comprises:
- a source for generating a pulsed laser beam;
- an optical means for focusing the laser beam into a pattern having a plurality of focal points;
- an optical scanner for moving the pattern of focal points along a spiral path, wherein movement of the pattern relative to a central axis is characterized by a variable angular velocity “ω”, and a variable radius “r”;
- and
- a computer means connected to the optical scanner for moving the pattern in a first phase wherein a radial spacing “Δr” between spiral lines, and the product “rω”, are held substantially constant as “r” is decreased from a radius r1 to a radius r2, and for moving the pattern in a second phase wherein “ω” is held constant and the radial spacing “Δr” is proportionally increased as “r” is further decreased from the radius r2 to a radius r3.
A system for Performing ophthalmic laser surgery which comprises:
- a source for generating a pulsed laser beam;
- a means for splitting the laser beam into a pattern having a plurality of focal points;
- an optical means for moving the pattern along a path in accordance with a predetermined protocol;
- and
- a computer means for synchronizing a movement of the beam splitting means with the movement of the pattern along a predetermined portion of the path.
A method for performing ophthalmic laser surgery which comprises the steps of:
- generating a pulsed laser beam, wherein the laser beam has an energy of approximately 4.5 μJ and each pulse has a duration less than one picosecond, and wherein a pulse is fired approximately every 25 μsec;
- splitting each pulse of the laser beam into a pattern having a plurality of focal points, with the energy at each focal point being approximately 1.5 μJ and with each focal point in the pattern having a separation from an adjacent focal point of approximately 20 μm;
- moving the pattern of focal points along a spiral path, wherein movement of the pattern relative to a central axis is characterized by a variable angular velocity “ω”, and a variable radius “r”, and wherein the pattern is moved through a distance of approximately 30 μm between each pulse;
- and
- synchronizing the splitting step and the moving step to follow a protocol having a first phase wherein a radial spacing “Δr” between spiral lines, and the product “rω”, are held substantially constant as “r” is decreased from a radius r1 of approximately 4.5 millimeters to a radius r2 of approximately 0.85 millimeters, and having a second phase wherein “ω” is held constant and the radial spacing “Δr” is proportionally increased as “r” is further decreased from the radius r2 of approximately 0.85 millimeters to a radius r3 of approximately 0.5 millimeters.
Dependencies are inferred from the claim text.