UK charity The Eyecare Trust has discovered that more than one-in-ten of us cannot properly process a stereoscopic 3D image.
If you've experienced headaches or visual discomfort when watching a 3D film then you could be one of 6 million people with "poor binocular vision", the company stated on its website.
You see, 3D signals require both eyes to work together, but 12 per cent of people (in the UK) have a "visual impairment" that leads to an "inconsistency" when processing the two images and the three spatial dimensions.
"You may not have realised that you have poor binocular vision before because your brain will often try to compensate for any visual inadequacies," the website warned.
"If left untreated binocular disorders such as amblyopia can affect your ability to read well and result in a greater propensity to suffer from screen fatigue when working at a [visual display unit] or watching TV for long periods of time."
The "good news", however, is that this can be diagnosed during an eye test and fixed with a bit of visual therapy of a fetching new pair of spectacles. Maybe they sell those too.
Last week, Ubisoft told Eurogamer that a 3DTV will be in every home in three years. "We can't ignore it," UK marketing boss Murray Pannell said.