Moviegoers have enjoyed the eye-popping 3-D animation of the blockbuster hit Avatar. But did you know millions of people can't see 3-D at all? The technology can even cause headaches and nausea in some, but the problem can be corrected with vision therapy.Katie Pace knew from a very young age that her vision was different than others. However, the problem was not identified until she saw some of her elementary school students succeed through vision therapy, which led her to give it a shot."When I came in here I was reading so slowly in silent reading," said Pace. "My silent reading fluency was that of a fifth-grader."Dr. Lynn F. Hellerstein had seen the symptoms before."Katie had some significant difficulties in eye coordination, and tracking and focusing skills," said Hellerstein. "When she read, she'd lose her place, she'd skip words, and she'd get headaches."Sometimes she would even get nauseous. Last fall, at 27 years old, Pace began vision therapy, in order to keep up with the reading necessary to obtain her doctorate in education, and help children who struggle like she did."I thought it was a vision problem, and every time it came back that I was 20/20 vision," said Pace. "And lo and behold Dr. Hellerstein figured out that I had eye teaming and binocular difficulties."Research indicates that up to 56 percent of those 18 to 38 years of age have one or more problems with binocular vision, and therefore have difficulty seeing 3-D."It's a coordination problem," said Hellerstein. "So what we are doing is training the brain to learn how to track better, focus, use both eyes together, appreciate depth, and improve eye hand coordination."Vision therapy trains the eyes to work together so the brain properly merges the separate images, from each eye, into one. 3-D technology exaggerates that separation. In the past, Pace has avoided 3-D movies and action films, which cause her discomfort."The problem is that many people don't use both eyes well together," said Hellerstein. "Either they shut off an eye or they struggle with their eye coordination. The end result, they may or may not see the depth."Vision therapy is working for Pace, who's now seeing a remarkable change in her life."Unbelievable, an unbelievable difference in my quality of life," said Pace. "In a way, I feel like I'm playing catch up. I want to read everything all at once."Vision insurance typically covers the initial evaluation, and medical insurance sometimes covers the actual vision therapy.You can find a list of optometrists throughout the country who provide vision therapy by clicking here, www.covd.org.