Method for corneal curvature variations

Abstract

A method for refractive correction of the eye in order to improve the vision of the eye while not adversely affecting its natural asphericity is described. The method involves determining the amount of correction necessary, selecting an intrastromal corneal ring (ICR) of appropriate thickness to obtain the necessary correction from a selection of ICRs of varying thickness, and inserting the ICR into the corneal stroma. The method may be useful for the correction of mypoia and excessive astigmatism.

We claim: 
     
       1. A method for refractive correction of a human eye for the purpose of improving the vision of said eye without adversely affecting its natural asphericity, said method comprising: (a) determining an amount of refractive correction necessary for improved vision in said eye;   (b) providing a plurality of intrastromal corneal rings (ICRs) of varying thickness;   (c) selecting from said plurality of ICRs an ICR of a thickness that provides said amount of refractive correction; and   (d) inserting the selected ICR into the corneal stroma of said eye.   
     
     
       2. The method of claim 1 wherein the thickness of the ICR is between 0.05 and 0.60 mm. 
     
     
       3. The method of claim 1 wherein the refractive correction is between 1.0 and 18.0 diopters. 
     
     
       4. The method of claim 1 wherein the refractive correction is between 1.0 and 2.0 diopters and the ICR is 0.25 mm thick. 
     
     
       5. The method of claim 1 wherein the refractive correction is between 2.0 and 4.0 diopters and the ICR is 0.30 mm thick. 
     
     
       6. The method of claim 1 wherein the refractive correction is between 4.0 and 8.0 diopters and the ICR is 0.35 mm thick. 
     
     
       7. The method of claim 1 wherein the refractive correction is between 6.0 and 10.0 diopters and the ICR is 0.40 mm thick. 
     
     
       8. The method of claim 1 wherein the refractive correction is between 8.0 and 15.0 diopters and the ICR is 0.45 mm thick. 
     
     
       9. A method for correcting myopia in a human eye, said method comprising: (a) determining an amount of refractive correction necessary to correct said myopia;   (b) providing a plurality of intrastromal corneal rings (ICRs) of varying thickness;   (c) selecting from said plurality of ICRs an ICR of a thickness that provides said amount of refractive correction; and   (d) inserting the selected ICR into the corneal stroma of the eye.   
     
     
       10. The method of claim 9 wherein the thickness of the ICR is between 0.05 and 0.60 mm. 
     
     
       11. The method of claim 9 wherein the refractive correction is between 1.0 and 18.0 diopters. 
     
     
       12. The method of claim 9 wherein the refractive correction is between 1.0 and 2.0 diopters and the ICR is 0.5 mm thick. 
     
     
       13. The method of claim 9 wherein the refractive correction is between 2.0 and 4.0 diopters and the ICR is 0.30 mm thick. 
     
     
       14. The method of claim 9 wherein the refractive correction is between 4.0 and 8.0 diopters and the ICR is 0.35 mm thick. 
     
     
       15. The method of claim 9 wherein the refractive correction is between 6.0 and 10.0 diopters and the ICR is 0.40 mm thick. 
     
     
       16. The method of claim 9 wherein the refractive correction is between 8.0 and 15.0 diopters and the ICR is 0.45 mm thick. 
     
     
       17. A method for alleviating excessive astigmatism in a human eye said method comprising: (a) determining an amount of refractive correction necessary for alleviating the excessive astigmatism in said eye;   (b) providing a plurality of intrastromal corneal rings (ICRs) of varying thickness;   (c) selecting from said plurality of ICRs an ICR of a thickness that provides said amount of refractive correction; and   (d) inserting the selected ICR into the corneal stroma of the eye.   
     
     
       18. The method of claim 17 wherein the intrastromal corneal ring has a thickness of between about 0.05 and 0.60 mm. .Iadd. 
     
     
       19.  The method of claim 1 wherein the inserting the selected ICR into the corneal stroma of the eye includes the steps of (d1) placing a keratotomy incision peripherally into the corneal stroma;   (d2) inserting a channelling blade into the incision and cutting a circular channel into the corneal stroma;   (d3) removing the channelling blade from the circular channel; and   (d4) inserting the selected ICR into the channel, the selected ICR being in the form of a generally circular member having split end portions, said inserting the selected ICR into the circular channel being effected by inserting one of the split end portions into the circular channel and threading the remainder of the ICR into the circular channel following the split end portion. .Iaddend..Iadd.20. The method of claim 19 further comprising the step of   (d5) securing the split ends to one another. .Iaddend..Iadd.21. The method of claim 9 wherein the inserting the selected ICR into the corneal stroma of the eye includes the steps of   (d1) placing a keratotomy incision peripherally into the corneal stroma;   (d2) inserting a channelling blade into the incision and cutting a circular channel into the corneal stroma;   (d3) removing the channelling blade from the circular channel; and   (d4) inserting the selected ICR into the channel, the selected ICR being in the form of a generally circular member having split end portions, said inserting the selected ICR into the circular channel being effected by inserting one of the split end portions into the circular channel and threading the remainder of the ICR into the circular channel following the split end portion. .Iaddend..Iadd.22. The method of claim 21 further comprising the step of   
     
     
       (d5) securing the split ends to one another. .Iaddend..Iadd.23.  The method of claim 17 wherein the inserting the selected ICR into the corneal stroma of the eye includes the steps of (d1) placing a keratotomy incision peripherally into the corneal stroma;   (d2) inserting a channelling blade into the incision and cutting a circular channel into the corneal stroma;   (d3) removing the channelling blade from the circular channel; and   (d4) inserting the selected ICR into the channel, the selected ICR being in the form of a generally circular member having split end portions, said inserting the selected ICR into the circular channel being effected by inserting one of the split end portions into the circular channel and threading the remainder of the ICR into the circular channel following the split end portion. .Iaddend..Iadd.24. The method of claim 23 further comprising the step of   (d5) securing the split ends to one another. .Iaddend.