Vision is an extremely complex sense. A common misconception is that vision is the same as sight. When people talk about vision, they often think of the Snellen Chart and the 20/20 line. This actually refers to “sight” or our “central” vision – the system that helps us identify clarity and detail. Our second system, the “peripheral” vision, is equally important to help orient us in our day to day life. Our peripheral vision is important for motion processing and orientation. Today’s blog will be about central vs peripheral vision.
To help better explain the importance of both these systems, I will use the example of a Window paradigm. From the picture above, the image on the right represents a window while the image on the left represents a scotoma (or an inverted window – where the central information is blocked out). When you look at the image on the right, you can immediately deduce a beach scene. However, the gist of the scene can still be deduced from observing the scotoma picture on the left even when the key central items of interest (the beach essentials) are missing from the scene.
A balance of these two systems play an important role in reading. We use our central vision to identify the words we are actively reading then we use our peripheral vision to help guide our eyes to where they need to land next so that we can read the subsequent words in the sentence. If our central vision wasn’t working, we would not be able to see the actual word. However, if our peripheral vision wasn’t working, our eyes would possibly direct us to a few words down a few lines versus the next word in the sentence. Comprehension would be near impossible.
The peripheral system helps us identify “where” while our central system identify “what”. Both peripheral and central vision are important to help us make sense and efficiently function in this visual world.