Which test incorporates true depth into its design and does not require glasses?

• A. Lang stereo test
• B. Frisby stereo test
• C. Random Dot E
• D. Stereo Fly

Answer: (B)

The test with true depth without glasses relies on actual three-dimensional separation in the scene. Frisby stereo stimuli place patterns at different physical distances behind a viewing surface, so both eyes naturally receive different viewpoints as you look. That real separation provides depth perception without any need for glasses, making it the test that incorporates true depth into its design.

In contrast, the other tests present depth through binocular disparity in a two-image display or coded patterns that typically require filters or glasses to separate the images for each eye. Without those glasses, the depth cue in those tests isn’t accessible.