The 3D effect in films is achieved by having two overlapping images. The 3D glasses filter out one image at a time so that the left eye sees one and the right eye sees the other. Together, the brain interprets this as three-dimensional. But what happens when you watch 3D films without the glasses?

3D is fundamentally more strenuous on the eyes than 2D. However, if you see the images through the 3D glasses, the visual muscle is trained accordingly to interpret the images correctly. The eyes learn to focus correctly. In the beginning, you may get a headache after a while, even if you watch with 3D glasses. But over time, the visual muscle becomes stronger and more flexible.

Without the 3D glasses, both eyes see both overlapping images at the same time. This leads to a blurred whole image. This can lead to the eyes not being able to adjust properly and may be permanently harmful. However, this only happens if you watch a lot of 3D TV on a regular basis without the glasses. If you walk through the living room while someone else is watching a 3D film and watch it for a few minutes, it is not a big deal.

Children's eyes are still developing and they should therefore not watch 3D without the appropriate glasses.