The frame has a shallow rabbet which extends from the nasal region of one eye rim, through {HEAD ~ the nasal region} of the bridge, into {TAIL ~ the nasal region} of the other eye rim, and has a predetermined depth 
The frame has a shallow rabbet which extends from the nasal region of one eye rim , through { HEAD ~ the nasal region } of the bridge , into { TAIL ~ the nasal region } of the other eye rim , and has a predetermined depth
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH