Actually, it is a classical word, meaning 'with beautiful eyes'. opos is in the genitive, so that's where the meaning comes from. I'd assume that the contemporary meaning is one of 'looking at things through eyes that are preprogrammed to see things as beautiful'. I guess a more coherent definition would be perceiving more beauty in something than there actually is.

http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0057%3Aentry%3D%2352907 (the site can take a long time to load.)