Digital technology is making the 3-D experience like nothing before, but many people still say trying to see in stereo leaves them with a headache, stomachache or both.

That could be a sign of an undiagnosed vision problem. And there may be a way to fix it.

For decades, 3-D was seen as more of a gimmick than an art form. Today’s three-dimensional experience is challenging that perception.

But even in this advanced form, 3-D is leaving some viewers feeling sick. Some patients describe the feeling of an ocular headache that comes from behind the eyes. Other complaints include nausea, dizziness and fatigue. There are no hard numbers, but it’s estimated anywhere from 4 to 10 percent of the population can’t watch or tolerate 3-D.

Three-dimensional film requires each eye to see a different image at the same time. Many people may have minor vision problems that aren’t evident on a day-to-day basis. Watching 3-D may unmask the issues. They include things such as lazy eye or convergence insufficiency, which means the eyes are not tuning in properly to focus.

During a 3-D movie, if focusing isn’t spot-on, you can experience problems.

Often, these problems can be fixed with vision therapy – a series of patient-specific exercises that "teach" the eyes how to work together again.

Patients with a mild form of eye teaming dysfunction known as convergence insufficiency might see the 3-D image; however, the demand on their eyes can create fatigue and strain and make it uncomfortable to enjoy.

Sue Berry, in her autobiography, "Fixing My Gaze," discusses her lack of normal 3-D vision through most of her life. As a neuroscientist, Berry knew there must be some way to restore her lack of 3-D vision. She sought out an optometrist who spent 12 months doing vision therapy activities in the office and at home. The results: Berry now has normal 3-D vision and describes how amazing it was to see objects "popping out" at her for the first time.

If you or a loved one has difficulty tolerating 3-D movies, it could be a sign of an underlying vision problem. Be sure to discuss this with your eye doctor at your next comprehensive examination.

For more information about Merrimack Vision Care, call 424-0404 or visit merrimackvision.com.