When I was in college, I took a philosophy course in which the professor posed the question, “What is a chair?” To answer the question, you have to consider the essential characteristics.

The conventional definition of a chair might be a piece of furniture designed for sitting on that has a seat, arms, legs and back. However, if you take away one or more of these characteristics, when is a chair no longer a chair? In other words, what gives a chair its “chair-ness”?
If you asked me a few years ago how I would define “eyewear,” I would have said that at its most basic, eyewear consists of a fashionable frame holding a pair of lenses that protect your eyes and help you see better. As we enter the age of wearable technology though, the definition of “eyewear” is becoming mutable. New technologies, many of them electronic, are being incorporated into what we traditionally think of as eyewear. And that leads to some interesting questions.

For instance, is eyewear still eyewear if it no longer serves its two primary purposes, enhancing vision or being a fashion accessory? Does it have to have a lens? Does it even have to have a frame, or can it simply have a thin metal headband, a la Google Glass?

I would argue for a broad definition of eyewear that covers a variety of form factors. This would include everything from goggles with heads-up displays, GPS and Bluetooth to sunglasses with built-in video cameras to the Zeiss cinemizer, a sleek-looking device that lets you watch 3-D movies and play virtual reality games. I would also include products like The PSiO, a device that has no lenses but offers synchronized sound and light stimulation programs on an inner facing screen that are designed to relax the wearer. (That’s me above trying out The PSiO at the Consumer Electronics Show last January.)

It’s time to rethink basic assumptions about eyewear. Consumers are already doing it, and those of us in the eyewear business need to keep pace.