B'Elanna and Tom wearing 3D glasses
3D glasses were a novelty form of eyewear used by movie-goers in the mid to late 20th century. When watching a three-dimensional film, wearing the glasses allowed for the processing of special effects and other details not seen in a standard film production.
In 2377, Tom Paris and B'Elanna Torres used the spectacles in a holodeck recreation of a movie theater to watch a double feature of early Earth films. (VOY: "Repression")