For people who need prescription (nearsightedness , farsightedness , astigmatism ) but, want to wear Oakley Tombstone model. 
This must be the perfect solution . 
You could enjoy sport activities with Tombstone prescription lenses  without damage Plutonite (original Oakley lenses) 
 
This Small wide clip could maximize the vision range by wide width of eye rim
 
Oakley inserts prescription