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