Method and system for modifying eye tissue and intraocular lenses
A system for ophthalmic surgery includes a laser source configured to deliver an ultraviolet laser beam comprising laser pulses having a wavelength between 320 nm and 370 nm to photodecompose one or more intraocular targets within the eye with chromophore absorbance. The pulse energy, the pulse duration, and the focal spot are such that an irradiance at the focal spot is sufficient to photodecompose the one or more intraocular targets without exceeding a threshold of formation of a plasma and an associated cavitation event. An optical system operatively coupled to the laser source and configured to focus the ultraviolet laser beam to a focal spot and direct the focal spot in a pattern into the one or more intraocular targets. The optical system focuses the laser beam at a numerical aperture that provides for the focal spot to be scanned over a scan range of 6 mm to 10 mm.
1. A system for ophthalmic surgery of an eye of a patient, comprising:
a laser source, configured to alternatively deliver an ultraviolet treatment laser beam and an ultraviolet probe laser beam, each laser beam comprising a plurality of ultraviolet laser pulses, wherein a pulse energy of the ultraviolet probe laser beam is lower than a pulse energy of the ultraviolet treatment laser beam;
an optical system operatively coupled to the laser source and configured to direct the laser beams;
an imaging system operatively coupled to the laser source and optical system and configured to detect a back reflected light from the eye; and
a controller coupled to the laser source, the optical system and the imaging system, and programmed to operate the laser source, the optical system and the imaging system to:
focus the ultraviolet probe laser beam to a focal spot and direct the focal spot of the ultraviolet probe laser beam in a imaging scan pattern into at least one intraocular target of the eye and to confocally detect back reflected light of the probe laser beam from the at least one intraocular target, thereby obtaining image data corresponding to the at least one intraocular target;
automatically generate a treatment scan pattern based at least in part on the image data; and
focus the ultraviolet treatment laser beam to a focal spot and direct the focal spot of the ultraviolet treatment laser beam in the treatment scan pattern into the at least one intraocular target, wherein the ultraviolet treatment laser in the treatment scan pattern alters the at least one intraocular target; and
wherein a spacing between at least two adjacent focal spots in the imaging scan is greater than a spot spacing between at least two adjacent focal spots in the treatment scan of the same intraocular target.
2. The system of claim 1 , wherein the at least one intraocular target is selected from a group consisting of a cornea, a limbus, a sclera, a lens capsule, a crystalline lens, and a synthetic intraocular lens implant.
3. The system of claim 1 , wherein the ultraviolet treatment laser in the treatment scan pattern creates one or more cuts in the at least one intraocular target, the one or more cuts being selected from the group consisting of one or more corneal relaxing incisions, one or more limbal relaxing incisions, one or more astigmatic keratotomies, one or more corneal flaps, one or more corneal transplant shapes, and one or more capsulotomies.
4. The system of claim 1 , wherein the ultraviolet treatment laser in the treatment scan pattern changes an index of refraction of the at least one intraocular target.
5. The system of claim 1 , wherein each of the ultraviolet treatment laser beam and the ultraviolet probe laser beam has a wavelength between 320 nanometers and 370 nanometers, wherein the ultraviolet treatment laser beam has a pulse duration between 1 picosecond and 100 nanoseconds, and a pulse energy between 0.01 microJoules and 500 microJoules.
6. The system of claim 5 , wherein the wavelength is 355 nm.
7. The system of claim 5 , wherein the pulse duration is between 400 picoseconds and 700 picoseconds.
8. The system of claim 5 , wherein the pulse energy is between 0.5 microJoules and 10 microJoules.
9. The system of claim 5 , wherein each of the ultraviolet treatment laser beam and the ultraviolet probe laser beam has a repetition rate of between 500 Hertz and 500 kiloHertz.
10. The system of claim 5 , wherein a diameter of the focal spot of each of the ultraviolet treatment laser beam and the ultraviolet probe laser beam is between 0.5 microns and 10 microns within the at least one intraocular target.
11. The system of claim 5 , wherein an irradiance of the ultraviolet treatment laser beam at the focal spot is less than or equal to 120 gigawatts per square centimeter.
12. The system of claim 1 , wherein the optical system has a numerical aperture of less than 0.6 and a scan range of 6 mm to 10 mm in a direction lateral to a Z-axis aligned with the laser beam.
13. The system of claim 12 , wherein the numerical aperture of the system is 0.05 to 0.4.
14. The system of claim 1 , wherein the controller is further programmed to operate the imaging system to monitor for occurrence of a cavitation event associated with formation of plasma, and in response to detection of a cavitation event, to reduce the pulse energy of the treatment laser beam or the probe laser beam.