Humans can see 3-D images with only one eye, according to new research, suggesting a future in which the technology could become cheaper and more accessible.

Simply looking through a small hole is enough to experience 3-D, says Dhanraj Vishwanath, a psychologist at the University of St. Andrews in Scotland. His research was published in the journal Psychological Science.

The 3-D technology that's currently used in movies and other media relies on two visual images, one from each eye, combining in the viewer's brain to produce 3-D's extra layer of depth.

But Vishwanath's research suggests that both eyes aren't needed.

"We have demonstrated experimentally, for the first time, that the same 'special way' in which depth is experienced in 3D movies can also be experienced by looking at a normal picture with one eye viewing through a small aperture (circular hole).

"While this effect has been known for a long time, it is usually dismissed," he said in a release from the university. "Now we have shown that it is in fact real, and the perceptual results are exactly like stereoscopic 3D, the kind seen in 3D movies."

In recent years, 3-D has become an emerging technology for blockbuster movies, video games, TV and other media. But it also causes headaches, dizziness and even nausea for as many as 10%of the people who watch it. Some experts believe that cumbersome 3-D glasses are a primary reason why the technology hasn't caught on with TV viewers.

The St. Andrews researchers say that, with the approach they explored, people with only one eye or those with problems watching 3-D with both eyes could still experience its "compelling" effect.

"Many of these people don't know what it means to see in 3D because they have never experienced it," Vishwanath said. "Our findings and preliminary results suggest that our method could be used to allow people with misaligned eyes … to experience what it is like to actually see in 3D."

He said the study could have implications for movie producers and other industries. Vishwanath suggested that 3-D could one day be produced by dramatically increasing the resolution of images. That method would also decrease eye fatigue and some of the other side effects people report from wearing 3-D glasses.

The St. Andrews team is now testing the theory with a larger group of subjects. They plan to release more findings on 3-D this year.