What is parafoveal vision?

Parafoveal vision is the area of vision just outside the central point of fixation. It is an extension of foveal vision and is the area in which you can see clearly when you are reading. Parafoveal vision extends for approximately 5 degrees of visual angle from the fovea, which is about the width of your thumb when held at arms’ length.

Parafoveal vision is necessary for reading because the eyes move quickly across the page, and fixate on each word briefly before moving on. This means that only a small part of each word is seen clearly. The information from the parafoveal area is used to fill in the details of the word being read and to predict the words that will come next.

Parafoveal vision is less acute than foveal vision, but it still allows us to perceive fine details and color information. The visual system can use information from the parafoveal area to build a composite image of what is being viewed. This is why we perceive a relatively stable and clear image of our surroundings despite the fact that our eyes are constantly moving.

Overall, parafoveal vision is an important part of our visual system that helps us read, navigate our environment, and perceive details even when we are not looking directly at them.