Laser-induced protection shield in laser surgery

1. An ophthalmic surgical method, the method comprising:

determining a surgical target region in an eye;

selecting a protection region between the surgical target region and a photosensitive tissue located distal to the surgical target region;

estimating a damage-threshold of the photosensitive tissue and a protection-threshold of the protection region;

applying preliminary laser-pulses to the protection region with parameters between the damage-threshold and the protection threshold at a focus spot of the laser pulses to form a protection barrier;

applying surgical laser pulses to the surgical target region with at least one parameter above the damage threshold;

wherein the estimating the damage-threshold of the photosensitive tissue comprises: estimating damage-threshold laser parameters, wherein laser pulses applied with the damage-threshold laser parameters are capable of damaging the photosensitive tissue; and

wherein the estimating the protection-threshold of the protection region comprises: estimating protection-threshold laser parameters, wherein laser pulses applied with the protection-threshold laser parameters are capable of forming a protection barrier in the protection region.

2. The method of claim 1 , wherein the selecting the protection region comprises:

selecting a location and shape of the protection region so that a protection barrier formed in the protection region is capable of protecting the photosensitive tissue from damage by residual surgical laser pulses.

3. The method of claim 2 , wherein the protecting the photosensitive tissue comprises at least one of:

blocking, scattering, or absorbing the residual surgical laser pulses.

4. The method of claim 1 , wherein the selecting the protection region comprises:

determining a portion of a boundary of a nucleus of the eye.

5. The method of claim 1 , wherein the estimating the protection-threshold and the damage-threshold comprises at least one of:

analyzing characteristics of elements of a surgical laser system, preparatory and pre-operative measurements, observations of the eye of the patient, using calculations, using an age-based algorithm, using data obtained form cadaver experiments, and consulting data-bases.

6. The method of claim 1 , wherein the estimating the damage-threshold and the protection-threshold comprises:

estimating a laser pulse energy in the range of 0.5 microJ to 50 microJ;

estimating a laser pulse energy density at a focus point of the laser pulses in the range of 6×10 −3 microJ/micron 2 to 60 microJ/micron 2 ;

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

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

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

7. An eye-surgery method, the method comprising:

identifying a portion of a boundary of a nucleus in a lens of an eye;

estimating a damage-threshold of a retina and a protection-threshold of the nucleus;

applying preliminary laser pulses with laser parameters between the damage-threshold and the protection-threshold at a focal spot of the laser pulses to a protection region in a posterior region of the nucleus to form a protection barrier;

applying surgical laser pulses to a target region anterior to the protection barrier in the nucleus with at least one parameter above the damage-threshold;

wherein the estimating the damage-threshold of the retina comprises: estimating damage-threshold laser parameters, wherein laser pulses applied with the damage-threshold laser parameters are capable of damaging the retina;

wherein the estimating the protection-threshold of the nucleus comprises: estimating protection-threshold laser parameters, wherein laser pulses applied with the protection-threshold laser parameters to the protection region are capable of forming a protection barrier; and

wherein the applying the preliminary laser pulses comprises: applying the preliminary laser pulses with laser parameters ensuring that the preliminary laser pulses damage the retina only to an insubstantial degree; and forming the protection barrier so situated and shaped that it is capable of protecting the retina from residual surgical laser pulses.

8. The method of claim 7 , the identifying the portion of the boundary of the nucleus comprising:

generating spaced-apart probe-bubbles inside the lens;

observing a property of the generated probe-bubbles; and

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

9. The method of claim 8 , 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.

10. The method of claim 8 , wherein:

the observing a property of the generated probe-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.

11. The method of claim 8 , 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.

12. The method of claim 7 , wherein the estimating a protection-threshold and a damage-threshold comprises at least one of:

analyzing characteristics of elements of a surgical laser system, preparatory and pre-operative measurements, observations of the eye of the patient, using calculations, using an age-based algorithm, cadaver experiments, and consulting data-bases.

13. The method of claim 7 , wherein the estimating the damage-threshold and the protection-threshold comprises:

estimating a laser pulse energy in the range of 0.5 microJ to 50 microJ;

estimating a laser pulse energy density at a focus point of the laser pulses in the range of 6×10 −3 microJ/micron 2 to 60 microJ/micron 2 ;

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

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

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

14. The method of claim 7 , wherein the applying surgical laser pulses comprises at least one of:

disrupting, fragmenting, and emulsifying a portion of the nucleus.

15. A surgical method for protecting a photosensitive tissue distal to a target of photodisruption, the method comprising:

determining a surgical target region in a body of a subject;

selecting a protection region between the surgical target region and the photosensitive tissue;

estimating a damage-threshold of the photosensitive tissue and a protection-threshold of the protection region;

applying preliminary laser-pulses to the protection region with parameters between the damage-threshold and the protection threshold at a focal spot of the laser pulses to form a protection barrier;

applying surgical laser pulses to the surgical target region with at least one parameter above the damage-threshold;

wherein the estimating the damage-threshold of the photosensitive tissue comprises: estimating damage-threshold laser parameters, wherein laser pulses applied with the damage-threshold laser parameters are capable of damaging the photosensitive tissue; and

wherein the estimating the protection-threshold of the protection region comprises: estimating protection-threshold laser parameters, wherein laser pulses applied with the protection-threshold laser parameters are capable of forming a protection barrier in the protection region.