Photodisruptive Treatment of Crystalline Lens

• US 20090149840A1
• Filed: 09/05/2008
• Published: 06/11/2009
• Est. Priority Date: 09/06/2007
• Status: Abandoned Application

• Current Assignee: Alcon LenSx, Inc. (Alcon Incorporated)
• Original Assignee: Alcon LenSx, Inc. (Alcon Incorporated)
• Inventors: KURTZ, RONALD M.
• Application Number:
  US12/205,842
• Publication Number:
  US 20090149840A1
• Time in Patent Office: Days
• US Class Current: 606/4
• CPC Class Codes: A61F 2009/0087 Lens
• CPC Class Codes: A61F 2009/00897 Scanning mechanisms or algorithms
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00825 for photodisruption

Abstract

Techniques, apparatus and systems for providing photodisruptive treatment of the crystalline lens of the eye are described. For example, a method of treating a lens region of an eye with a laser includes 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.

Claims

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.