Ever watched a movie in 3-D?  How did it make you feel?

More than half of people who put on 3-D glasses admitted the movie made them feel sick to some degree.

55 percent of moviegoers had at least one physical complaint after the experience.

According to research, the most common complaints were that their eyes felt tired or they had a headache. Almost 11 percent felt like they wanted to puke.

Overall, people's symptoms were usually mild and seemed to disappear as soon as they took off their 3-D glasses, except if it triggered a headache.

Almost half complained that the film hurt their eyes. It strained their eyes, blurred their vision, or made it hard to focus. About one in five 3-D viewers felt somewhat disoriented at the theater. They had a headache, or felt off-balance or dizzy, whether their eyes were open or shut.

The study also found that women, especially those with a history of car sickness, vertigo, or frequent headache, might be more vulnerable to the symptoms.

As for why some people find it harder to handle 3-D movies than others do, it's because the distance where our eyes converge is different from where they focus. That causes extra work for the visual system and could lead to annoying side effects.

The most vulnerable people are those with unequal vision in both eyes or those with small vision misalignments.