Method and Systems for Laser Treatment of Presbyopia Using Offset Imaging

Abstract

An ophthalmic surgery system and method for treating presbyopia by performing ablative photodecomposition of the corneal surface. The offset image of a variable aperture, such as a variable width slit and variable diameter iris diaphragm, is scanned in a preselected pattern to perform ablative sculpting of predetermined portions of a corneal surface. The scanning is performed to ablate an optical zone sized to match the patient pupil with a peripheral transition zone outside the pupil. The shape of the ablated optical zone is different from the shape of the final optical correction on the anterior surface of the cornea. The optical zone corrects for near-vision centrally and far-vision peripherally. A movable image displacement mechanism enables radial displacement and angular rotation of the profiled beam exiting from the variable aperture. The invention enables wide area treatment with a laser having a narrower beam than the treatment area, and can be used in the treatment of many conditions in conjunction with presbyopia such as hyperopia, hyperopic astigmatism and irregular refractive aberrations.

1 . A method of treating a first eye and a second eye of a patient to mitigate presbyopia, the method comprising:
 providing a presbyopia correction covering a desired optical power range by:
 correcting the first eye to have a first average refraction and a first range of focus, the first range of focus being less than the desired optical power range; 
 correcting the second eye to have a second average refraction and a second range of focus, the second range of focus being less than the desired optical power range; 
   wherein the first range and the second range of focus combine to provide focus throughout the desired optical power range.   
     
     
         2 . The method of  claim 1 , wherein the first average refraction differs with the second average refraction by 0.5 D to 2.5 D after correction. 
     
     
         3 . The method of  claim 2 , wherein the first average refraction differs with the second average refraction by 1 D to 2 D after correction. 
     
     
         4 . The method of  claim 1 , wherein the first eye is corrected for far vision. 
     
     
         5 . The method of  claim 3 , wherein the second eye is corrected for near vision. 
     
     
         6 . The method of  claim 1 , wherein the desired optical power range is between a 1 D range and a 4 D range. 
     
     
         7 . The method of  claim 1 , wherein the desired optical power range is about a 3 D range. 
     
     
         8 . The method of  claim 5 , wherein the first range of focus for the first eye is between a 0.5 D range and a 2.0 D range after correction. 
     
     
         9 . The method of  claim 8 , wherein the first range of focus for the first eye is between a 1.0 D range and a 1.5 D range after correction. 
     
     
         10 . The method of  claim 8 , wherein the first average refraction for the first eye is between 0.25 D and −1.75 D after correction. 
     
     
         11 . The method of  claim 10 , wherein the first average refraction for the first eye is about plano after correction. 
     
     
         12 . The method of  claim 6 , wherein the second range of focus for the second eye is between a 0.5 D range and a 2.0 D range after correction. 
     
     
         13 . The method of  claim 12 , wherein the second range of focus for the second eye is between a 1.0 D range and a 1.5 D range after correction. 
     
     
         14 . The method of  claim 13 , wherein the second average refraction for the second eye is between −1.25 D and −2.25 D after correction. 
     
     
         15 . The method of  claim 14 , wherein the second average refraction for the second eye is about −1.5 D after correction. 
     
     
         16 . A system for reshaping a first eye and a second eye of a patient to mitigate presbyopia, the system comprising:
 a laser for generating an electromagnetic radiation beam;   an optical scanning system for directing the electromagnetic radiation beam along a beam path; and   a processing system coupled with the laser and the optical scanning system, the processing system configured to provide a presbyopia correction covering a desired optical power range by:
 identifying a first aspheric shape modification for the first eye and a second aspheric shape modification for the second eye, the first aspheric shape modification providing a first average refraction and a first range of focus to the first eye, and the second aspheric shape modification providing a second average refraction and a second range of focus for the second eye, the first range of focus and the second range of focus each being less than the desired optical power range; and 
 wherein the first range of focus and the second range of focus combine to provide focus throughout the desired optical power range. 
   
     
     
         17 . The system of  claim 16 , wherein the first aspheric shape modification corrects the first eye for far vision and wherein the second aspheric shape modification corrects the second eye for near vision. 
     
     
         18 . The system of  claim 17 , wherein the first range of focus for the first eye and the second range of focus for the second eye is between a 1.0 D range and a 2.0 D range after correction. 
     
     
         19 . The system of  claim 18 , wherein the first average refraction for the first eye is between 0.25 D and −0.75 D after correction and wherein the second average refraction for the second eye is between −1.25 D and −2.25 D after correction. 
     
     
         20 . A method of treating a first eye and a second eye of a patient to mitigate presbyopia, the method comprising:
 providing a presbyopia correction covering at least a 3 D range by:
 correcting the first eye to have a 0.25 D to a −0.75 D average refraction and at least a 1.5 D range of focus; 
 correcting the second eye to have a −1.25 D to a −2.25 D average refraction and at least a 1.5 D range of focus; 
   wherein the at least 1.5 D range of focus for the first eye and the at least 1.5 D range of focus for the second eye combine to provide focus throughout the at least 3 D range.