The 3D effect on the left and right is achieved through the use of stereoscopic vision, where each eye sees a slightly different image. This creates a sense of depth and allows the brain to interpret the images as a three-dimensional scene.

In the context of 3D media, such as movies or video games, the left and right images are typically presented to each eye separately. This is done through various methods, including:

1. Anaglyph 3D: This method uses two different colored lenses (usually red and blue) over each eye to filter the images. The left eye sees the left image, and the right eye sees the right image, creating a 3D effect.

2. Active Shutter 3D: This method uses synchronized shutters for each eye, which open and close rapidly in sync with the refresh rate of the screen. This alternates which eye sees the left or right image, creating a 3D effect.

3. Passive 3D: Similar to anaglyph, this method uses polarized lenses for each eye. The left lens filters the left image, and the right lens filters the right image, creating a 3D effect.

The effectiveness of the 3D effect on the left and right depends on several factors:

Content Quality: High-quality 3D content with well-defined depth cues tends to produce a more convincing 3D effect. Poorly designed 3D content can lead to eye strain and a less immersive experience.

Viewer Distance: The optimal distance from the screen for a 3D effect varies depending on the technology used. For example, active shutter 3D requires a closer distance to the screen to avoid screen-door effect, while passive 3D can be viewed from a greater distance.

Eye Focusing: The ability to focus on objects at different distances is crucial for a comfortable 3D experience. Some individuals may experience discomfort or eye strain if they cannot easily switch between near and far objects.

According to a study published in the Journal of Vision, the perceived depth in 3D images is influenced by the angle of view and the presence of depth cues such as shadows and perspective. For instance, a 3D image with a wide angle of view and clear depth cues is more likely to produce a convincing 3D effect compared to a narrow angle of view with minimal depth cues.

In conclusion, the 3D effect on the left and right is achieved through the use of stereoscopic vision, with various technologies enabling this effect. The effectiveness of the 3D experience is influenced by content quality, viewer distance, and the ability to focus on objects at different distances.