I stumbled upon this tidbit recently: Sources indicate that the Chinese invented sunglasses in the 12th or 13th centuries to hide the eyes of judges in the courtroom.

Today, we think of sunglasses as ways to protect eyes from glare. As a blue-eye who wears contact lenses, I'm extremely photosensitive: Even on cloudy days, I need sunglasses to see without discomfort. In fact, I wear huge, dark lenses to block as much glare as I can. The sunglasses I run in have smaller and lighter lenses, and there are times I have to tilt my head a certain way to keep the sun out.

I'm not trying to project any specific image with my sunglasses, I don't think. Sure, I picked sunglasses that I thought were more attractive on me than other, similar options. But that's it. I don't wear sunglasses inside and I don't wear them to camouflage my emotions or thoughts—although I suppose they do, when I'm wearing them. Is that a side benefit? I don't know. I don't have anything to hide.

Other people do wear sunglasses to hide: To avoid eye contact, which is so personal and revealing, and to conceal abnormal-looking eyes (like the blind, people with shiners, and weepers and allergy-sufferers).

And other people do wear sunglasses to project an image--or a personal brand. Think of Jackie O and her dark, round sunglasses. Jack Nicholson and his medium-dark soft rectangular lenses. (In fact, I found a funny and apropos quote from Nicholson in his IMDB biography: "With my sunglasses on, I'm Jack Nicholson. Without them, I'm fat and seventy.")

And why did Corey Hart wear his sunglasses at night? The lyrics aren’t clear.

An interesting article by Audrey Nelson in Psychology Today pointed out that the mouth and eyes account for 56 percent of our attention when we look at another person. These features are the most expressive of our emotional state. However, she also noted that staring makes people uncomfortable—as does avoiding eye contact.

Not looking at someone shows lack of respect—people focus on people they feel are important, Nelson wrote. Studies show that people in subordinate positions look at people in superior positions more often. Conversely, staring is confrontational. When stared at, people in inferior roles look away more quickly than people in power positions.

That means if you're wearing sunglasses, you may be hiding your status or trying to elevate yourself above others: Sunglasses allow you to watch and even stare without people knowing you’re looking, preserving your purportedly disinterested "power" position. Hm.

So: Other than for sun protection, why do you wear your sunglasses?