Apple devices using iOS 7 making some people sick

CUPERTINO, Calif., Sept. 27 (UPI) -- The iOS 7 powering U.S. tech giant Apple's iPhones and iPads overhauls the interface and has a boatload of animation -- and some say it's making them sick.

Not green with envy, but green behind the gills, FoxNews.com reported Friday.

"The zoom animations everywhere on the new iOS 7 are literally making me nauseous and giving me a headache. It's exactly how I used to get carsick if I tried to read in the car," one iPhone user posted on Apple's support forums.

"Have headaches and nausea for past 3 days," another user posted. "Can't stand to look at my phone screen anymore while opening/closing apps. I just close my eyes or look away."

Dr. George Kikano, division chief of family medicine at UH Case Medical Center in Ohio, told FoxNews.com users likely were correct when reporting the car sickness.

The culprit is a new "parallax" function that causes the phone's background to move subtly back and forth, which can lead to an effect similar to carsickness, he said.

"The inner ear is responsible for balance, the eyes for vision," Kikano said. "When things are out of sync you feel dizzy, nauseous. Some people get it, some people don't, and some people get used to it."

Kikano, an iPhone 5S user, said when Apple introduced the parallax feature, it added a setting to turn it off in the settings menu.

Charles Oman, a former NASA director who studied motion sickness, told ABC News he's hesitant to call it motion sickness.

"It takes a couple minutes of sustained stimulation to activate motion sickness," he said. "If it were an immersive environment ... then I can believe it, but it's a little harder to believe on the small screens."