According to China Daily [see here], a middle-aged female developed acute angle-closure glaucoma after attending a 3D showing of the movie Avatar. Presumably, pupil dilation induced by the dark environment for a lengthy period of time precipitated this attack. Curiously, however, the patient must have been staring at the bright movie screen; this, by itself, should have caused pupil constriction unless totally negated by the Polaroid glasses worn for the 3D effect. Unfortunately, no experimental data are available for a reasonable explanation.
Ultimately, the deciding factor is the structure of the angle in the eyes of each individual. A patient with extremely narrow angle will have a higher risk that often can be confirmed with the darkroom test. Intermittent narrow angle glaucoma cases can be examined with the darkroom prone-position test in which the patient stays for 45 min without going to sleep. And the IOP measured immediately after. An increase of 8 mm Hg is considered positive.
Not only the movies, 3D TVs are rapidly moving into the consumer products arena. The common complaint of asthenopia owing to the contraction of medial recti can be resolved with the incorporation of base-out prisms in the 3D glasses. Strangely, no manufacturers have bothered with this implementation thus far even though the cost is minimal.
A recent report of stroke/death of a hypertensive man in Taiwan [see here] after watching Avatar is most likely coincidental. It could have been from seeing any exciting movies, not necessarily the 3D effect per se; although medical issues do await further investigation.
All new technologies will have unintended side-effects, real or imagined, e.g., the much disputed correlation between cell phone use and brain tumor (there is none, BTW). The introduction of the pseudo-3D visual world to the populace is no exception. This may spur some much-needed research. Very simply put: who wouldn't want to enjoy 3D in both comfort and safety.