I don't think this is where I ran across that information first, but here is a bit of information on Bishop from Lloyd Schwartz at Atlantic Unbound, who claims to have known her:
"The most poignant -- and frightening -- image in "Sonnet" is the empty mirror. Always shy and self-conscious, Bishop hated the way she looked, hated looking at herself. She'd grown heavier from the years of cortisone she had to take for her asthma; her hair had turned gray. She felt old and bloated, though everyone else thought she looked more elegant than ever. I was visiting her the day her copy of Richard Howard's coffee-table anthology Preferences arrived, with a beautiful full-page photograph of her by Thomas Victor. She excused herself, went into her bedroom, and tore the page with the photograph out of the book. She would have preferred to look into an empty mirror, even given the sinister implications."
http://www.theatlantic.com/unbound/p...ngs/bishop.htm
Julie