Surgical knife blade

Abstract

A surgical knife blade of the type primarily intended for making incisions in the eye, though suitable for incising virtually any spherical surface, is disclosed. The blade is uniquely characterized by its construction to include cutting edge bevels of different transverse dimension on the anterior surface of the blade with respect to the transverse dimension of corresponding bevels on the posterior surface of the blade, such that the blade of this invention will incise a substantially straight, perpendicular cut into the eye or other spherical surface.

What is claimed is:  
     
       1. A surgical knife blade of the type primarily intended for making incisions in the eye, said blade comprising: an elongated body having proximal and distal ends, anterior and posterior opposing surfaces, a shoulder intermediate said proximal and distal ends, first and second longitudinal sides between said proximal end and said shoulder, and first and second cutting edges between said shoulder and said distal end; said first and second cutting edges being formed by the intersection of first and second anterior bevels on said anterior surface with opposed first and second posterior bevels on said posterior surface, said intersection of said first and second anterior bevels with said first and second posterior bevels disposing said first and second cutting edges on a plane that is closer to the plane of said anterior surface than to the plane of said posterior surface at said distal end; and said first and second longitudinal sides being formed by the intersection of third and fourth anterior bevels on said anterior surface with opposed third and fourth posterior bevels on said posterior surface, said third and fourth anterior bevels being substantially equal to said first and second anterior bevels at said shoulder and said third and fourth posterior bevels being substantially equal to said first and second posterior bevels at said shoulder, said third and fourth anterior bevels each having a transverse dimension that is different from the corresponding transverse dimension of said third and fourth posterior bevels. 
     
     
       2. A blade as in claim  1  wherein said blade comprises a diamond. 
     
     
       3. A blade as in claim  1  wherein said first and second longitudinal sides are substantially parallel. 
     
     
       4. A blade as in claim  1  further comprising a handle attached to said proximal end. 
     
     
       5. A blade as in claim  1  wherein said shoulder comprises a width of about 2.5-3.2 mm. 
     
     
       6. A blade as in claim  1  wherein said intersection of said first and second anterior bevels with said first and second posterior bevels disposes said first and second cutting edges on a plane that is closer to the plane of said posterior surface than to the plane of said anterior surface at said shoulder. 
     
     
       7. A blade as in claim  6  wherein said first and second anterior bevels are about 0.1 mm in length at said distal end and about 0.5 mm in length at said shoulder. 
     
     
       8. A blade as in claim  7  wherein said first and second posterior bevels are about 0.8 mm in length at said distal end and about 0.1 mm in length at said shoulder. 
     
     
       9. A blade as in claim  6  wherein said third and fourth anterior bevels are about 0.5 mm in length. 
     
     
       10. A blade as in claim  9  wherein said third and fourth posterior bevels are about 0.1 mm in length. 
     
     
       11. A blade as in claim  1  wherein said first and second longitudinal edges diverge outwardly from said shoulder to said proximal end. 
     
     
       12. A blade as in claim  11  wherein said intersection of said third and fourth anterior bevels with said third and fourth posterior bevels disposes said first and second longitudinal sides on a plane that is closer to the plane of said posterior surface than to the plane of said anterior surface at said proximal end. 
     
     
       13. A blade as in claim  12  wherein said third and fourth anterior bevels are about 0.5 mm in length at said shoulder and are greater than about 0.5 mm at said proximal end and said third and fourth posterior bevels are about 0.1 mm in length at said shoulder and are less than about 0.1 mm at said proximal end. 
     
     
       14. A surgical knife blade of the type primarily intended for making incisions in a cornea of an eye, the blade being adapted for attachment to a handle, comprising: 
       
         an elongated body having a proximal end and a distal end and anterior and posterior planar surfaces;  
       
         bevels formed in the planar surfaces, the bevels being symmetrical on each side of the anterior and the posterior planar surfaces and non - symmetrical as compared between the anterior and posterior planar surfaces, the bevels intersecting to form first and second cutting edges, the cutting edges intersecting to form a tip at the distal end.    
     
     
       15. The blade of claim  14  wherein the blade is formed from diamond.  
     
     
       16. The blade of claim  15  wherein the planar surfaces are disposed such that the distance therebetween is about  0 . 2  mm.  
     
     
       17. The blade of claim  14  further comprising a pair of shoulders formed at an intersection between the first and second cutting edges and a pair of longitudinal sides extending between the shoulders and the proximal end.  
     
     
       18. The blade of claim  17  wherein the pair of shoulders is disposed such that the distance therebetween is in the range from about  2 . 5  mm to about  3 . 2  mm.  
     
     
       19. The blade of claim  17  wherein the longitudinal sides are parallel.  
     
     
       20. The blade of claim  17  further comprising bevels formed in the planar surfaces between the shoulders and the proximal end, the bevels intersecting to form third and fourth cutting edges, the third and fourth cutting edges intersecting the first and second cutting edges at the shoulders.  
     
     
       21. The blade of claim  20  wherein the third and fourth cutting edges diverge outwardly from the shoulders to the proximal end.  
     
     
       22. A surgical knife blade of the type primarily intended for making incisions in a cornea of an eye, the blade being adapted for attachment to a handle, comprising: 
       
         an elongated body having a proximal end and a distal end and first and second planar surfaces;  
       
         bevels formed in the planar surfaces, the bevels being symmetrical on each side of the first and the second planar surfaces and non - symmetrical as compared between the first and second planar surfaces, the bevels intersecting to form first and second cutting edges, the cutting edges intersecting to form a tip at the distal end.    
     
     
       23. The blade of claim  22  wherein the blade is formed from diamond.  
     
     
       24. The blade of claim  22  wherein the planar surfaces are disposed such that the distance therebetween is about  0 . 2  mm.  
     
     
       25. The blade of claim  22  further comprising a pair of shoulders formed at an intersection between the first and second cutting edges and a pair of longitudinal sides extending between the shoulders and the proximal end.  
     
     
       26. The blade of claim  25  wherein the pair of shoulders is disposed such that the distance therebetween is in the range from about  2 . 5  mm to about  3 . 2  mm.  
     
     
       27. The blade of claim  25  wherein the longitudinal sides are parallel.  
     
     
       28. The blade of claim  25  further comprising bevels formed in the planar surfaces between the shoulders and the proximal end, the bevels intersecting to form third and fourth cutting edges, the third and fourth cutting edges intersecting the first and second cutting edges at the shoulders.  
     
     
       29. The blade of claim  28  wherein the third and fourth cutting edges diverge outwardly from the shoulders to the proximal end.  
     
     
       30. A surgical knife blade of the type primarily intended for making incisions in an eye, comprising: 
       
         an elongated body having proximal and distal ends, first and second opposing planar surfaces, a pair of shoulders intermediate the proximal and distal ends, and first and second cutting edges between the pair of shoulders and the distal end, the cutting edges being formed by the intersection of bevels in the first and second opposing planar surfaces and being included in a plane, the plane being closer to the plane of the first planar surface than to the plane of the second planar surface at the distal end; and  
       
       
         first and second longitudinal sides between the proximal end and the pair of shoulders, the longitudinal sides being formed by the intersection of bevels in the first planar surface with opposed bevels in the second planar surface, the bevels being disposed such that they substantially match the bevels forming the first and second cutting edges at the pair of shoulders.  
       
     
     
       31. The blade of claim  30  wherein the blade is formed from diamond.  
     
     
       32. The blade of claim  30  wherein the longitudinal sides diverge between the pair of shoulders and the proximal end.