Stereoscopic vision is a fascinating and fundamental concept in the world of vision and visual perception. Although it may sound like a technical term, it actually refers to a capacity that all human beings possess and plays a crucial role in our daily lives.
At its core, stereoscopic vision refers to the ability to perceive the world in three dimensions, meaning we can experience depth and distance between objects.
Stereoscopic vision is based on the idea that we have two eyes that are separated by a certain horizontal distance, which is known as binocular vision. This separation between the eyes allows us to see the same scene from two slightly different points of view. Therefore each eye receives a slightly different image of an object or scene, and our brain combines those two images into a single three-dimensional visual perception.
To better understand how stereoscopic vision works, we can do a simple experiment. Extend one arm in front of you with your thumb raised and close one eye. Then, alternate between closing your right and left eyes. You will notice that the object you are looking at appears to move slightly from one side to the other. This is due to the difference in the perspective that each eye has of the object. When you open both eyes, your brain combines these two perspectives into a single three-dimensional image, allowing you to accurately perceive depth and separation between your finger and the background.
When we look at an object, the light from that object hits our eyes from different angles due to the separation between the eyes. Each eye captures a slightly different image of the object. These two images are sent to the brain, which processes them and combines them into a single three-dimensional image. This process is called binocular fusion.
Binocular fusion is what allows us to perceive depth and distance between objects. When an object is closer to us, the difference between the images captured by each eye is greater, resulting in greater depth perception. On the other hand, when an object is far away, the difference between the images is smaller, and we perceive that object as distant.
The importance of stereoscopy
Stereoscopic vision is essential for many everyday activities. For example, when you drive a car, you evaluate the distance between your vehicle and near and far objects on the road. This capability allows you to change lanes safely, park accurately, and avoid collisions. It is also important in the perception of distance when walking, which helps you avoid obstacles and interact with the environment safely.
In addition to everyday life, stereoscopic vision plays a vital role in various professions. Surgeons, for example, depend on this ability to perform precise and delicate surgeries. Three-dimensional vision allows them to perceive the depth of tissues and anatomical structures, which is crucial to carry out successful surgical procedures.
Architects and designers use stereoscopic vision to create plans and three-dimensional representations of buildings and spaces. This allows them to visualize what a project will look like in the real world and make necessary adjustments to ensure its functionality and aesthetics.
In the world of entertainment, stereoscopic vision is the basis of 3D technology and stereoscopy, which is used in movies, games, and virtual experiences. Thanks to this technology, we can immerse ourselves in three-dimensional worlds and experience the sensation that objects and characters are really close or far from us.
But stereoscopic vision is not limited to just humans. It is also important in the lives of other animals, particularly predators that hunt prey. Stereoscopic vision allows them to accurately assess distance and successfully calculate the jumps and movements required to catch their prey.
Why can it make some people dizzy?
It is important to note that stereoscopic vision is only one part of our visual system. Our eyes also focus on near or far objects through a process called accommodation. Additionally, they can move in a coordinated manner to follow moving objects. All of this is integrated into our visual system to provide us with a complete and accurate perception of the world around us.
When we watch a 3D video or experiment with virtual reality glasses we have a stereoscopic sensation very similar to reality. The process itself is the same, each eye is receiving a different image.
It is important to mention that not all people have the same capacity for stereoscopic vision. Some people may have difficulties due to functional or pathological conditions, such as strabismus (a deviation of the eyes) or amblyopia (lazy eye). In such cases, depth perception may be limited or absent. Fortunately, there are optometric therapies and treatments that can improve stereoscopic vision in some cases.
So, why are there people who, when they go to the cinema to see a 3D movie or use VR glasses, feel uncomfortable, dizzy or the image splits, but in real life they don’t have any problems. The answer is that in the stereoscopy technique the eyes are always focusing at the same distance, not like in real life, and the fact of having to coordinate the two eyes and have perception of distances without changing the focus there are subjects who do not tolerate it because their visual parameters are very inflexible. But this, like any visual skill, can be trained.
In the same way we can experience fatigue or dizziness in a poor stereoscopic production, with an exaggerated 3D sensation or with continuous camera movements.