Photodisruptive Treatment of Crystalline Lens

1 . A method of treating a lens region of an eye with a laser, comprising:

identifying a boundary of the hard lens region;

selecting a laser-parameter to enable a photodisruptive procedure in the hard lens region and to control a spreading of bubbles in the hard lens region;

modifying a mechanical property of a posterior portion of the hard lens region in a proximity of the identified boundary by the photodisruptive procedure; and

modifying a mechanical property of a portion anterior to the modified posterior portion of the hard lens region by the photodisruptive procedure.

2 . The method of claim 1 , the identifying the boundary of the hard lens region comprising:

generating spaced-apart probe-bubbles inside the lens;

observing a property of the generated probe-bubbles; and

identifying a portion of the boundary in connection to the observed property of the probe-bubbles.

3 . The method of claim 2 , wherein:

the observing a property of the generated bubbles comprises:

identifying one or more probe-bubbles exhibiting a first growth rate; and

identifying one or more probe-bubbles exhibiting a second growth rate different from the first growth rate; and

the identifying the portion of the boundary comprises:

identifying a boundary between the probe-bubbles exhibiting the first growth rate and the probe-bubbles exhibiting the second growth rate.

4 . The method of claim 2 , wherein:

the observing a property of the generated bubbles comprises:

applying ultrasound to the lens;

identifying one or more probe-bubbles exhibiting a first response to the ultrasound; and

identifying one or more probe-bubbles exhibiting a second response different from the first response; and

the identifying the portion of the boundary comprises:

identifying a boundary between the probe-bubbles exhibiting the first response and the probe-bubbles exhibiting the second response.

5 . The method of claim 2 , wherein the identifying the boundary comprises at least one of:

observing the probe-bubbles with an optical imaging method; and

observing the probe bubbles with an optical coherence tomography.

6 . The method of claim 1 , wherein the identifying the boundary comprises:

using at least one of a preoperative and intra-operative identification of the boundary.

7 . The method of claim 1 , wherein the identifying the boundary comprises:

identifying the boundary of the hard lens region in a group of eyes;

correlating the boundary of the hard lens region of the eyes with a measurable characteristic of the eyes; and

establishing a boundary-database which records the correlation between the boundary of the hard lens region and the other measurable characteristic.

8 . The method of claim 7 , wherein the identifying the boundary comprises:

determining the measurable characteristic of an eye of a patient; and

identifying the boundary by using the boundary-database.

9 . The method of claim 1 , wherein the identifying the boundary comprises at least one of:

performing a calculation based on a measurable characteristic of an eye of a patient; and

performing an age-based determination of the boundary.

10 . The method of claim 1 , wherein the selecting the laser-parameter comprises:

selecting a laser-parameter between a disruption-threshold and a spread-threshold.

11 . The method of claim 10 , wherein the selecting the laser parameter comprises:

selecting a laser pulse energy in the range of 1 microJ to 25 microJ;

selecting a duration of a laser pulse in the range of 0.01 picoseconds to 50 picoseconds;

selecting a frequency of applying laser pulses in the range of 10 kHz to 100 MHz; and

selecting a separation distance of target regions of laser pulses in the range of 1 micron to 50 microns.

12 . The method of claim 1 , wherein the modifying the mechanical property of a portion of the hard lens region includes at least one of:

disrupting, fragmenting, and emulsifying a tissue in the hard lens region.

13 . The method of claim 1 wherein the identifying a boundary of the hard lens region comprises:

identifying a hard lens region with an equatorial diameter in the range of 6 to 8 mm and an axial diameter of 2 to 3.5 mm.

14 . The method of claim 1 , further comprising:

creating an incision on a capsule of the lens;

removing a portion of the hard lens region with the modified mechanical property from the lens through the incision with at least one of:

applying aspiration through the incision; and

applying suction through the incision.

15 . A method for fragmenting a crystalline lens of an eye with a photodisruptive laser, comprising:

selecting a central region of the lens for photodisruption;

selecting a laser characteristic to achieve photodisruption and control of an expansion of gas in the selected central region; and

directing laser pulses with the selected laser characteristic on a target area moving in a posterior to anterior direction in the selected central region of the lens.

16 . The method as in claim 15 , wherein the selecting of the selected central region is based on at least one of:

a preoperative measurement of an optical or structural property of the treated central region of the lens; and

a preoperative measurement of the overall lens dimensions and the use of an age dependant algorithm.

17 . The method as in claim 15 , wherein the selecting of the laser characteristics comprises:

selecting at least one of an energy, a frequency, a pulse duration, and a spatial separation of two adjacent target areas of the laser pulses;

based on at least one of:

a preoperative measurement of lens optical properties, structural properties, overall lens dimensions and the use of an age dependant algorithm.

18 . The method of claim 15 , wherein the selecting the central region comprises:

generating a set of bubbles in the lens;

observing an optical or mechanical characteristics of the generated bubbles;

identifying a set of central bubbles with a characteristics indicating a first hardness of a surrounding tissue and a set of non-central bubbles with a characteristics indicating a second hardness of a surrounding tissue, wherein the first hardness is greater than the second hardness; and

identifying the central region based on a location of the set of central bubbles.

19 . A laser system for fragmenting the crystalline lens of an eye, comprising:

a pulsed laser configured to generate a laser beam of laser pulses; and

a laser controller, wherein the laser controller is:

configured to direct the laser beam to a sequence of target areas aligned in a posterior to anterior direction in a selected hard lens region of an eye for photodisruption; and

configured to control the pulsed laser to generate a laser beam with laser-parameters sufficient:

to create photodisruption in the selected hard lens region; and

to generate gas bubbles with a predetermined expansion properties in the hard lens region.

20 . The laser system of claim 19 , wherein the laser controller is configured to control the pulsed laser to generate laser pulses with:

an energy in the range of approximately 1 microJ to 25 microJ;

a separation of adjacent target areas in the range of approximately 1 micron to 50 microns;

a duration in the range of approximately 0.01 picoseconds to 50 picoseconds; and

a repetition rate in the range of 10 kHz to 100 MHz.

21 . The laser system of claim 19 , further comprising:

an optical system, configured to observe a property of probe-bubbles, generated in the lens; and

a processor, configured to be able to identify a hard lens region within the eye using the observed property of the probe-bubbles.