eagles' eyes
... that colour vision with resolution and clarity are the most prominent features of eagles' eyes , and hence the epithet given to sharp-sighted people is "eagle-eyed”?
... that colour vision with resolution and clarity are the most prominent features of <b id="mwCZI"><a href="./Eagle_eye" id="mwCZM" rel="mw:WikiLink" title="Eagle eye">eagles' eyes</a></b> <i id="mwCZQ">(pictured)</i>, and hence the epithet given to sharp-sighted people is "eagle-eyed”?