Laser-assisted thermal separation of tissue
A laser-assisted method for fully or partially separating tissue such as collagen containing tissue is provided. In one embodiment, the method pertains to a capsulorhexis whereby the laser-assisted method is applied to the lens capsule. A light-absorbing agent is added into or onto the tissue. A light beam with a wavelength capable of being absorbed by the light absorbing agent is then directed at the tissue to cause a thermal effect at the tissue following a predetermined closed curve with the goal to avoid irregularity or potential tears in the resulting rim of the tissue.
1. A device for thermally separating tissue in the anterior lens capsule of an eye in a procedure creating an opening in the anterior lens capsule, the device comprising:
a laser device programmed to direct a laser beam along a predetermined closed curve on the anterior lens capsule;
wherein the laser beam power, wavelength, and diameter at the anterior lens capsule are selected such that the laser beam is absorbed by a light absorbing agent in or on the anterior lens capsule to locally heat the anterior lens capsule along the closed curve without ablation of the anterior lens capsule, thereby separating the anterior lens capsule along the closed curve to form an area of anterior lens capsule tissue inside the closed curve and an area of anterior lens capsule tissue outside the closed curve, the lens capsule tissue outside the closed curve defining the boundary of the opening in the anterior lens capsule;
wherein the laser device is programmed to direct the laser beam in a single pass starting at an initial point interior to the closed curve, then along the closed curve, and then to a final point interior to the closed curve;
wherein the laser beam diameter at the anterior lens capsule is 50 microns to 600 microns;
wherein the laser beam power at the anterior lens capsule is less than or equal to 1000 mW;
wherein the laser beam is directed along the closed curve at less than or equal to 10 millimeters/second; and
wherein absorption of the laser beam by the light absorbing agent causes a temperature increase at the anterior lens capsule along the closed curve of between 50 degrees Celsius and 150 degrees Celsius.
2. The device of claim 1 , wherein the light absorbing agent is added to the anterior lens capsule.
3. The device of claim 1 , wherein the laser beam is a continuous wave laser beam.
4. The device of claim 1 , wherein the closed curve is circular or elliptical.
5. The device of claim 1 , wherein the laser beam diameter at the anterior lens capsule is 100 microns to 300 microns.
6. The device of claim 1 , wherein absorption of the laser beam by the light absorbing agent causes a temperature increase at the anterior lens capsule along the closed curve of between 100 degrees Celsius and 120 degrees Celsius.
7. The device of claim 1 , comprising a laser device programmed to direct a visible laser beam along a visualization pattern on the anterior lens capsule to assist a user in selecting the location and size of the opening to be created in the anterior lens capsule.
8. The device of claim 1 , in combination with a surgical contact lens that increases the numerical aperture with which the laser beam is focusable onto the anterior lens capsule thereby reducing exposure of the retina and the fovea of the eye to the laser beam.
9. The device of claim 1 , wherein:
the laser beam is a continuous wave laser beam; and
the laser beam diameter at the anterior lens capsule is 100 microns to 300 microns.
10. The device of claim 9 , comprising a laser device programmed to direct a visible laser beam along a visualization pattern on the anterior lens capsule to assist a user in selecting the location and size of the opening to be created in the anterior lens capsule.
11. The device of claim 9 , wherein the light absorbing agent is added to the anterior lens capsule.
12. The device of claim 9 , in combination with a surgical contact lens that increases the numerical aperture with which the laser beam is focusable onto the anterior lens capsule thereby reducing exposure of the retina and the fovea of the eye to the laser beam.