Compound modulation transfer function for laser surgery and other optical applications

1. A method for determining an optical surface shape that mitigates or treats a vision condition of an eye of a particular patient, the method comprising:

determining an optical surface shape for the particular patient using a set of patient parameters for the specific patient with a compound modulation transfer function (CMTF), the compound modulation transfer function comprising a combination of modulation transfer functions (MTF's) at a plurality of distinct frequencies.

2. The method of claim 1 , wherein the CMTF is normalized to a diffraction limited MTF.

3. The method of claim 2 , wherein the MTF's at the plurality of distinct frequencies are combined in a linear combination.

4. The method of claim 3 , wherein the CMTF is calculated according to the following formula

CMTF

=

1

n

⁢

∑

i

=

1

n

⁢

α

i

⁢

h

i

,

where n is the number of MTF curves, α i is the reciprocal of the ith diffraction-limited MTF, and h i is the ith MTF curve.

5. The method of claim 1 , wherein the CMTF is calculated according to the following formula

F ( v )=(α 1 MTF 1 +α 2 MTF 2 +α 3 MTF 3 )/3

where MTF 1 , MTF 2 , and MTF 3 comprise MTF values ranging from about 5 cycles/degree to about 20 cycles/degree, from about 15 cycles/degree to about 45 cycle/degree, and from about 30 cycles/degree to about 75 cycles/degree, respectively.

6. The method of claim 5 , wherein MTF 1 , MTF 2 , and MTF 3 comprise MTF values of 10 cycles/degree, 20 cycles/degree and 30 cycles/degree, respectively.

7. The method of claim 5 , wherein weighting coefficients α 1 , α 2 , α 3 are chosen so that 1/α 1 , 1/α 2 , 1/α 3 are the diffraction-limited MTF at these spatial frequencies, respectively.

8. The method of claim 5 , wherein MTF 1 , MTF 2 , and MTF 3 comprise MTF values of 10 cycles/degree, 20 cycles/degree and 30 cycles/degree, respectively, and the vision condition comprises presbyopia.

9. The method of claim 1 , wherein one MTF at a spatial frequency corresponds to one angular extend of features of targets, and the compound MTF can be calculated as linear combination of MTF at different spatial frequencies normalized by a diffraction-limited MTF.

10. The method of claim 9 , wherein the CMTF is used to predict visual outcome.

11. The method of claim 1 , wherein the CMTF is calculated according to the following formula

CMTF

⁡

(

v

)

=

1

n

⁢

∑

i

=

1

n

⁢

α

i

⁢

MTF

i

⁡

(

v

)

where nu is visual vergence and α i is the reciprocal of the i-th diffraction-limited MTF.

12. The method of claim 11 , wherein the CMTF comprises three MTF curves at 10, 20 and 30 cycles per degree.

13. The method of claim 12 , wherein the CMTF comprises a value of about 1.

14. The method of claim 13 , wherein the CMTF comprises a value ranging from about 0.2 to about 0.3.

15. The method of claim 1 , wherein the CMTF is calculated over a vergence of 3 diopters.

16. The method of clam 1 , wherein the MTF's at the plurality of distinct frequencies comprise MTF's at 10, 20, and 30 cycles per degree.

17. The method of claim 1 , wherein the MTF's at the plurality of distinct frequencies comprise MTF's at 15, 30, and 60 cycles per degree.

18. The method of claim 1 , wherein the MTF's at the plurality of distinct frequencies comprise MTF's at 30, 45, and 60 cycles per degree.

19. The method of claim 1 , wherein the MTF's at the plurality of distinct frequencies comprise at least one MTF ranging from about 5 cycles/degree to about 20 cycles/degree, at least one MTF ranging from about 15 cycles/degree to about 45 cycles/degree, and at least one MTF ranging from about 30 cycles/degree to about 75 cycles/degree.

20. The method of claim 1 , wherein the CMTF is used in an optimization routine as a goal function.

21. The method of claim 1 , wherein the vision condition comprises presbyopia.

22. A system for establishing an optical surface shape that mitigates or treats a vision condition of an eye in a particular patient, the system comprising;

(a) an input that accepts a set of patient parameters; and

(b) a module comprising a tangible medium embodying machine-readable code that determines an optical surface shape for the particular patient based on the set of patient parameters, using a gauge of optical quality appropriate for the vision condition of the eye;

wherein the gauge of optical quality comprises a compound modulation transfer function (CMTF) parameter, the compound modulation transfer function parameter based on a CMTF comprising a combination of modulation transfer functions (MTF's) at a plurality of distinct frequencies.

23. A system for reprofiling a surface of a cornea of an eye of a particular patient from a first shape to a second shape having correctively improved optical properties, the system comprising:

(a) an input that accepts a set of patient parameters;

(b) a module comprising a tangible medium embodying machine-readable code that determines an optical surface shape for the particular patient based on the set of patient parameters, using a gauge of optical quality appropriate for a vision condition of the eye;

(c) a processor that generates an ablation profile; and

(d) a laser system that directs laser energy onto the cornea according to the ablation profile so as to reprofile a surface of the cornea from the first shape to the second shape, wherein the second shape corresponds to the determined optical surface shape;

wherein the gauge of optical quality comprises a compound modulation transfer function (CMTF) parameter, the compound modulation transfer function parameter based on a CMTF comprising a combination of modulation transfer functions (MTF's) at a plurality of distinct frequencies.