Understanding the Visual Field
The field of view of the human eye is the range of space that the human eye can see at rest, including up, down, left, right, and four directions. The breadth of the visual field is not only critical for daily activities, but is also one of the most important factors in assessing eye health.
Upper Visual Boundary
When a person looks straight ahead, they can generally see upward at an angle of about 60 degrees. This means that if the line of sight in front of them is taken as a 0-degree starting point, people are able to observe objects or sights that are 60 degrees higher than the direct line of sight, which is useful for observing objects high up in the sky or avoiding obstacles when playing sports.
Downward Visual Limit
The downward visual limit is usually a bit smaller than when going upward, about 70-75 degrees. This design allows humans to better see the pavement or obstacles beneath their feet when walking or performing other ground activities, thus ensuring safe walking.
Right and Left Vision Boundaries
In the left and right directions, a person's field of vision is much wider, typically reaching approximately 90 to 100 degrees. This wide field of vision allows a person to perceive movement from the side and is an important self-protection mechanism that helps to detect potential threats or opportunities in a timely manner.
The Synergistic Action of Eyes and Head Movement
The human eye's field of vision is capable of covering almost the entire surrounding environment, thanks to the combined effects of eye movement and head rotation. Although the field of view of each eye is limited, the synergistic action of the two eyes greatly expands the overall range of a person's field of vision, allowing them to better adapt to complex and changing environments.
Conclusion
Overall, the design of the human visual field takes into account the needs of survival and activity. Through a wide field of vision in four directions, up, down, left, right and left, human beings are able to effectively perceive their surroundings, which is of great significance for daily life and survival.