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 Normal size clip would be recommanded for people who have high myopia prescription , as we polish myopia lenses , it becomes thinner  . 
 
Oakley inserts prescription