The pain could last a week.
Betabeat reports that two of its writers who tested Google Glass experienced sharp pains about ten minutes into the demo. After continuously pressing Google for an explanation, the search engine giant put BetaBeat in touch with Dr. Eli Peli, a Harvard optometrist who was brought into the Explorer program as a consultant. Turns out that "ocular discomfort" is a common Glass-based problem.
The "headaches" are caused by the location of the screen. Google initially tried to place the display straight ahead or below the eye, but the screen obstructed the user's line of vision. So the only place to put the screen was above the eye (upper right). Unfortunately, looking up is uncomfortable; we're used to looking straight ahead or down towards our feet.
"The only people who look up a lot are some professionals like electricians and painters," Dr. Peli told Betabeat. "Most of us look either straight or down. It's well known that up is less comfortable."
Dr. Peli also added that when we look left or right, it's usually for a split second before our head turns in that direction. People typically don't look to the side for an extended duration. He provides an example, saying that when someone is standing on their leg for a long period of time, the person begins to feel tension. That's not how the leg is normally used.
"If you're looking at the Glass for a minute, you're holding it there for sixty times longer than normal," Dr. Peli added. He said that Glass users aren't getting headaches; users are merely straining their eye muscles. The pain will go away in a few days – a week at the most. Glass wearers will eventually get used to looking at an odd angle, or won't use Glass as much as they initially did.
"The recommendation is to not overdo it when you start," he said. "Use it in the recommended way right from the beginning."
Just weeks ago, Google opened the Glass doors to anyone willing to part with $1,500 USD. The company indicated that the Glass Explorer program is still an open beta of sorts. Previous reports claimed that Google will try to make the retail version of Glass available for everyone before the end of the year.