Motion parallax is a monocular cue that contributes significantly to our perception of depth, especially when we are moving. As we move, objects that are closer to us appear to move quickly past our field of vision, whereas distant objects appear to move more slowly. This difference in relative motion provides crucial information about the relative distances of objects. For instance, when driving, the nearby roadside objects like signs or trees seem to whiz past us, while distant objects such as mountains appear to move slowly. This cue is particularly important in providing depth information in dynamic environments, enhancing our ability to navigate effectively. It is a fundamental aspect of our visual perception system, allowing us to judge distances on the go, which is critical for activities like driving or walking in traffic.

The Ames Room illusion is a famous perceptual illusion that dramatically demonstrates the role of monocular cues in depth perception. In an Ames Room, a room is constructed with a trapezoidal shape but appears rectangular from a specific viewpoint due to peephole viewing. This construction distorts the viewer's perception of depth and size. Objects or people in one corner of the room appear significantly larger than those in another corner, even though they are the same size. This illusion exploits our reliance on certain depth cues, such as relative size and linear perspective, leading us to incorrect conclusions about the true size and distance of objects. It highlights how our depth perception can be easily fooled under certain conditions and underscores the importance of context and multiple cues in accurately perceiving depth.

Depth perception can change with age due to a variety of factors, including changes in the eyes and the brain. In older adults, depth perception can be affected by physiological changes such as reduced pupil size, which limits the amount of light entering the eye, and decreased lens flexibility, affecting the eye's ability to focus. These changes can lead to difficulties in perceiving depth, especially in low-light conditions. Moreover, age-related conditions like cataracts and glaucoma can further impair depth perception. There is also evidence suggesting that the neural processing of sensory information can slow down with age, potentially impacting the integration of depth cues. However, it's important to note that individual experiences vary, and many older adults retain effective depth perception. Regular eye examinations and corrective measures can help mitigate some of these age-related changes.

Artists skillfully manipulate depth cues in their work to create a sense of three-dimensionality on a flat surface. They often use linear perspective, making parallel lines converge in the distance to give the illusion of depth. Relative size is another tool, where objects intended to appear closer are drawn larger than those meant to be perceived as distant. Overlapping or interposition is used by placing some objects in front of others to create a sense of depth. Artists also use shading and light to imply texture and contours, further enhancing the perception of depth. Additionally, atmospheric perspective, where distant objects are rendered with less clarity and contrast than closer objects, is a technique employed to depict depth. These techniques demonstrate how artists can simulate depth perception cues to create realistic or intentionally distorted representations of space.

Depth cues play a critical role in the effectiveness of virtual reality (VR) and augmented reality (AR) experiences. These technologies aim to create immersive, three-dimensional environments, and the accurate simulation of depth cues is crucial for this. In VR, stereopsis is simulated by presenting slightly different images to each eye through a headset, creating a sense of depth similar to what we experience in the real world. Monocular cues like linear perspective, texture gradient, and light and shadow are also incorporated to enhance the depth perception within the virtual environment. In AR, where digital objects are superimposed onto the real world, depth cues are crucial for ensuring that these objects appear to exist within the user's real-world space. Accurate depth representation in VR and AR is not only essential for realism but also for user comfort, as inconsistencies in depth cues can lead to disorientation or motion sickness.