METHODS AND SYSTEMS FOR CHANGING A REFRACTIVE PROPERTY OF AN IMPLANTABLE INTRAOCULAR LENS
A method of altering a refractive property of a crosslinked acrylic polymer material by irradiating the material with a high energy pulsed laser beam to change its refractive index. The method is used to alter the refractive property, and hence the optical power, of an implantable intraocular lens after implantation in the patient's eye. In some examples, the wavelength of the laser beam is in the far red and near IR range and the light is absorbed by the crosslinked acrylic polymer via two-photon absorption at high laser pulse energy. The method also includes designing laser beam scan patterns that compensate for effects of multiphone absorption such as a shift in the depth of the laser pulse absorption location, and compensate for effects caused by high laser pulse energy such as thermal lensing. The method can be used to form a Fresnel lens in the optical zone.
1 .- 20 . (canceled)
21 . A method of altering a refractive property of an implantable intraocular lens having an optic body including an optical zone and a peripheral zone surrounding the optical zone, comprising:
generating a pulsed light beam using a light source and a light delivery optical system, wherein the pulsed light beam has a top hat light intensity profile which is flat in a center region of the profile, or a vortex light intensity profile which peaks at radial positions away from a center of the profile; and
irradiating the optical zone of the intraocular lens with the light beam,
wherein the optical zone comprises a material configured to change its refractive index upon irradiation by the light beam, thereby altering a refractive property of the intraocular lens.
22 . The method of claim 21 , wherein the optical zone comprises a crosslinked acrylic material, and wherein irradiation with the light beam produces a predetermined change in the refractive index of the crosslinked acrylic polymer.
23 . The method of claim 22 , wherein the change in refractive index relative to the pre-irradiation refractive index at a location within the crosslinked acrylic polymer is linearly related with a total energy of the irradiation with the light source within a defined total energy range.
24 . The method of claim 21 , further comprising:
before the irradiating step, implanting the intraocular lens in a patient's eye, wherein the irradiating step is performed while the intraocular lens is in the patient's eye.
25 . The method of claim 21 , wherein the irradiating step is performed while the intraocular lens is outside of any patient's eye.
26 . The method of claim 21 , wherein the pulsed light beam contains nanosecond laser pulses.
27 . The method of claim 21 , wherein the pulsed light beam has a wavelength of 400 to 450 nm or 650 to 800 nm.
28 . The method of claim 21 , wherein the pulsed light beam has a wavelength of 650 to 800 nm, a pulse energy of 10 nJ to 10 uJ, a pulse duration of 10 fs to 10 ps, a pulse repetition rate of 10 to 1000 kHz, a laser focus spot size of 5 to 25 μm, and a numerical aperture of 0.01 to 0.15.
29 . The method of claim 21 , wherein the pulsed light beam has a wavelength of 680 to 720 nm, a pulse energy of 100 nJ to 2 uJ, a pulse duration of 100 to 600 fs, a pulse repetition rate of 300 kHz, a laser focus spot size of 7 to 12 μm, and a numerical aperture of 0.03 to 0.12.