LENS DESIGN

OVERALL DIAMETER


The outside diameter of the lens is 
called the overall diameter (OAD) or 
overall size (OS).  

The OAD is specified in millimeters.  
For rigid corneal lenses the OAD is 
usually in the range of 8.0 mm to 
11.0 mm.  For hydrogel lenses it is 
12.0 mm to 16.0 mm.