Stabilizing delivered laser energy

• US 20050203494A1
• Filed: 03/09/2005
• Published: 09/15/2005
• Est. Priority Date: 03/15/2004
• Status: Active Grant

• Current Assignee: Amo Manufacturing Usa, Llc (Johnson & Johnson)
• Original Assignee: VISX Incorporated
• Inventors: Holliday, Keith
• Granted Patent: US 7,836,893 B2
• Time in Patent Office: Days
• US Class Current: 606/5
• CPC Class Codes: A61F 2009/00848 based on wavefront
• CPC Class Codes: A61F 2009/00855 Calibration of the laser system
• CPC Class Codes: A61F 2009/00872 Cornea
• CPC Class Codes: A61F 9/008 using laser
• CPC Class Codes: A61F 9/00804 Refractive treatments
• CPC Class Codes: A61F 9/00819 with photoablatable masks

Abstract

Systems and methods provide for stabilizing the amount of laser energy delivered to a target from a laser device. Generally, delivered laser energy is measured over multiple laser pulses or over time in the case of a constant wave laser. A decrease is then calculated in the delivered energy, the decrease being caused by accumulation of one or more substances, such as ozone, along the laser beam delivery path due to passage of the laser beam along the path. Using this calculated decrease, a laser device may be adjusted to compensate for the decrease in delivered energy due to the accumulated substance(s), thus stabilizing the amount of energy delivered to the target.

Claims

1. A method for stabilizing an amount of laser energy delivered to a target by a laser generating device, the method comprising:

measuring the amount of delivered laser energy arriving at or near a target from the laser generating device over a period of time;

calculating a decrease in the amount of delivered energy over time; and

adjusting the laser generating device to compensate for the decrease to stabilize the amount of delivered laser energy arriving at the target.

2. A method as in claim 1, wherein measuring the amount of delivered laser energy comprises measuring with a laser energy meter positioned at or near the target.

3. A method as in claim 2, wherein the laser energy meter is positioned on an opposite side of a partially transparent lens or mirror from the target.

4. A method as in claim 1, wherein measuring the amount of delivered laser energy comprises measuring delivered energy of multiple pulses of laser energy.

5. A method as in claim 1, wherein the amount of delivered laser energy comprises measuring delivered energy of a constant wave of laser energy.

6. A method as in claim 1, wherein calculating the decrease in the amount of delivered energy comprises calculating a decrease caused by passage of the laser energy along a delivery path, which causes an accumulation of at least one substance along the delivery path, the substance impeding subsequent passage of the laser energy.

7. A method as in claim 6, wherein the at least one substance comprises ozone, and wherein passage of the laser energy along the delivery path causes an amount of oxygen to be converted to ozone.

8. A method as in claim 6, wherein calculating the decrease in the amount of delivered energy comprises calculating a decrease in delivered energy of a pulse of laser energy compared to an immediately previously fired pulse of laser energy.

9. A method as in claim 8, wherein calculating the decrease comprises:

calculating an amount of decrease caused by accumulation of one or more substances in the delivery path of the laser energy; and

reducing the amount of the decrease caused by the accumulation by a factor of time between pulses of the laser energy, which time allows for dissipation of the substance(s).

10. A method as in claim 1, wherein adjusting the laser generating device comprises increasing an amount of laser energy provided from the laser generating device over time to compensate for accumulation of at least one substance along a delivery path of the laser energy caused by passage of the laser energy along the path.

11. A method as in claim 10, wherein the laser generating device is adjusted to compensate for accumulation of ozone along the delivery path.

12. A method as in claim 10, wherein adjusting the laser generating device further comprises reducing any increases in the amount of provided laser energy to compensate for time between pulses of laser energy, which time allows for dissipation of the substance(s).

13. A method as in claim 1, wherein the measuring, calculating and adjusting steps are performed during a calibration procedure for the laser generating device.

14. A method as in claim 13, further comprising performing a laser eye surgery procedure with the laser generating device after the calibration procedure.

15. A method as in claim 1, further comprising directing laser energy from the laser generating device toward the target.

16. A method as in claim 15, wherein the directed laser energy comprises pulsed laser energy.

17. A method as in claim 15, wherein the directed laser energy comprises constant wave laser energy.

18. A method for performing a laser eye surgery procedure, the method comprising:

calibrating a laser generating device, wherein calibrating comprises;

measuring the amount of delivered laser energy arriving at or near a target from the laser generating device over a period of time;

calculating a decrease in the amount of delivered energy over time; and

adjusting the laser generating device to compensate for the decrease so that the delivered laser energy arriving at the target remains approximately constant over time; and

performing the laser eye surgery procedure using the calibrated laser generating device.

19. A method for performing a laser eye surgery procedure, the method comprising:

directing an amount of laser energy from a laser generating device toward an eye; and

adjusting the amount of directed laser energy to compensate for accumulation of one or more substances along a delivery path of the laser energy to stabilize the amount of delivered laser energy that arrives at the eye.

20. A method as in claim 19, wherein the amount of directed laser energy is adjusted to compensate for accumulation of ozone along the delivery path.

21. A method as in claim 20, wherein the amount of directed laser energy is increased over time to compensate for accumulation of ozone along the delivery path and is decreased over time to compensate for time between pulses of the laser energy, which time allows the ozone to dissipate.

22. A system for performing a laser eye surgery procedure, the system comprising:

a laser energy generating device;

a laser energy measuring device disposed at or near a target for measuring delivered energy of the laser energy device; and

a processor coupled with the laser energy generating device and the laser energy measuring device for calculating an adjustment to the laser energy generating device to compensate for accumulation of one or more substances along a laser energy delivery path and for adjusting the laser energy generating device to stabilize an amount of delivered laser energy that arrives at a target of the laser eye surgery procedure.

23. A system as in claim 22, wherein the laser energy generating device provides pulsed laser energy.

24. A system as in claim 22, wherein the laser energy generating device provides constant wave laser energy.

25. A system as in claim 22, wherein the processor is calibrated before performing the laser eye surgery procedure.

26. A system as in claim 22, wherein the processor increases an amount of laser energy provided by the laser energy device to compensate for the accumulation of the substance(s) and decreases the provided laser energy to compensate for time between pulses of the laser energy, which time allows for dissipation of the substance(s).

27. A system as in claim 22, wherein the processor adjusts the laser energy generating device to compensate for accumulation of ozone along the delivery path.

28. A system for performing a laser eye surgery procedure, the system comprising:

a laser energy generating device; and

a processor coupled with the laser energy generating device for calculating an adjustment to the laser energy generating device to compensate for accumulation of one or more substances along a laser energy delivery path and for adjusting the laser energy generating device to stabilize an amount of delivered laser energy that arrives at a target of the laser eye surgery procedure,

wherein the processor is calibrated before performing the laser eye surgery procedure.