A groove is formed in an endpiece head to allow {HEAD ~ distal ends} of {TAIL ~ the head} to flex away from the lens and reduce the pressure on the lens 
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A groove is formed in an endpiece head to allow { HEAD ~ distal ends } of { TAIL ~ the head } to flex away from the lens and reduce the pressure on the lens
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH