I am not sure when it happened....but it may have been around age 45 for me. That was when I began to develop my current transparency. It's something you don't, or at least I didn't, realize was happening until I had totally un-seeable. There comes a time when you become just an object in a room. Perhaps it begins with people calling you "sir" or "ma'am" for the first time. It can't be the gray hair...heck, George Clooney has gray hair. Perhaps it's a hormonal thing. I remember well into my 40's...members of the opposite sex seemed to be interested in me. I was still young, and still wanted....and then...it happened...transparency...invisibility....It's like I am not even here. Anyone else ever feel that way?