Writing by Prof. Kent Caszlo, Professional Director, YAL
3D vision
3D vision is built on the difference in the point of view of both eyes, one to the right of the nose and the other to the left. When we look at two objects and their figures create equal angles in both eyes, we will see each of the objects once, without a 3D diagnosis.
This situation mainly occurs when the objects are on the imaginary circle line that is created when the angle in both eyes is equal. (The imaginary circle is called a heroptor.)
All points on the outline of the circle create an equal angle in both eyes.
If the objects we observe create different angles in both eyes but by small increments, we will interpret this visual event as 3D.
If the objects create large angle differences between the two eyes, we will see one of the objects double (twice).
3D vision depends on the existence and cooperation of both eyes and therefore does not occur in situations where there is single-eyed vision or strabismus.
In the range of up to 1-2 meters from us, 3D vision is very useful in evaluating depth and distance, beyond this range the angle between the two eyes is small and estimating the depth and distance because of angle differences is ineffective.
Depth vision
Depth vision is the ability to detect objects located at different distances from each other, beyond a range of 2 meters. When we mainly depend on sharp-eyed signs are studied (empirical) to see depth. These signs are processed and studied throughout our lives by the brain through visual and visual experiences.
Here's a list and examples of some of these symbols:
- Lighting perspective:
Since lighting almost always comes from above, we learn about depth by distinguishing between a bright area versus a shaded area. If we rotate the depth page in the images flips over.
- Overlap:
Objects that overlap each other mark for us that the hidden object is closer (before) the hidden.
- Relative size:
We learn to compare size to distance, larger objects are interpreted as closer.
Here's an example of how you can easily "cheat" the brain:
- Linear perspective:
Parallel lines appear to connect to a distant point on the horizon.
- Peralxa:
When we are in motion, nearby objects move faster and against our direction of motion, distant objects move slower and with our direction of motion.
- Atmospheric perspective:
The further away you look, the more the atmosphere blurs the image and we understand that these objects are further away.
In summary,
Although both 3D vision and depth diagnosis are learned vision skills, there is no doubt that the one-eyed signs (depth diagnosis) depend much more on visual learning throughout our lives and require more visual and long-term experiences in the development of the child. Therefore, for visually impaired children with much less random visual learning than the environment, more difficulties are expected in this area. There is no doubt that it can affect mobility and orientation.
