Second pass femtosecond laser for incomplete laser full or partial thickness corneal incisions
A method for forming an incision in an eye, the method including performing a first pass of a first laser beam along a path within an eye, wherein after completion of the first pass there exists a residual uncut layer at an anterior surface of a cornea of the eye. The method further including performing a second pass of a second laser beam only along a portion of the path that contains the residual uncut layer, wherein after completion of the second pass, the residual uncut layer is transformed into a full complete through surface incision.
1. A two-step method for forming an incision in an eye, the method comprising:
First, performing a first pass of a first laser beam along a path within a cornea of an eye, wherein after completion of said first pass there exists a partial cut in the cornea and anterior to the partial cut there exists a residual uncut layer of the cornea at an anterior surface of the cornea;
Second, performing a second pass of a second laser beam only along a portion of said path that contains said residual uncut layer, wherein after completion of said second pass, said residual uncut layer is fully cut, transforming the residual uncut layer and partial cut into a full complete incision through the cornea.
2. The method of claim 1 , wherein said first laser beam has a low numerical aperture and passes through a liquid-filled patient interface before penetrating said eye, and wherein said residual uncut layer is the result of said first laser beam passing through said liquid-filled patient interface.
3. The method of claim 1 , wherein said first laser beam has a different energy than said second laser beam.
4. The method of claim 3 , wherein said first laser beam is at a first energy that just exceeds a photodisruption threshold and said second laser beam is at a second energy that is higher than said first energy.
5. The method of claim 4 , wherein said first laser beam is scanned along said path at a different rate than said second laser beam is scanned along said portion of said path that contains said partial thickness incision.
6. The method of claim 1 , wherein said first laser beam is scanned along said path at a different rate than said second laser beam is scanned along said portion of said path that contains said partial thickness incision.
7. The method of claim 1 , wherein said path is a linear path and said portion of said path that contains said residual uncut layer is linear.
8. The method of claim 1 , wherein said path is an angular path and said portion of said path that contains said residual uncut layer is linear.
9. The method of claim 1 , wherein said path is an angular path and said portion of said path that contains said residual uncut layer is angular.
10. The method of claim 9 , wherein said angular path is a zig-zag angular path and said portion of said path that contains said residual uncut layer is L-shaped.
11. The method of claim 1 , wherein said first laser beam has a pulse width that is less than one femtosecond and said second laser beam has a pulse width that is less than one femtosecond.
12. The method of claim 1 , wherein after completion of said second pass, a full thickness corneal incision is formed.
13. The method of claim 1 , wherein after completion of said second pass, a partial thickness corneal incision is formed.