If our peripheral vision has such low resolution, one might wonder why we don’t see the world in a kind of tunnel vision where everything is out of focus except what we are directly looking at now. The resolution of our visual field is high in the center but much lower at the edges. As our peripheral vision narrows, the scanning becomes less effective, which slows our reading. Our peripheral vision prescans text ahead of our point of focus, providing information to our brain about what lies ahead, how far ahead to jump, which words to skip over, and where to pause. As we read, our eyes focus on one group of words, take them in, and then jump 1 ahead several words to take in the next group. It also reduces peoples’ ability to detect motion at the edges of their vision.Īge-related narrowing of peripheral vision also has a negative effect on reading. Reduced peripheral vision increases the chance of people missing error messages, warnings, or other information that appears away from where they are looking. Obviously, peripheral vision is needed to notice on-screen content that is not where our gaze is focused. Sometimes, I don’t even notice things on the edges of the screen. Like age-related farsightedness, this gradual narrowing of our field of vision is common and considered normal. By 70–80 years of age, most of us have lost 20–30 degrees from the edges of our visual field. How much worse? It varies, but on the average, we lose about 1–3 degrees from the edges of our visual field every 10 years. Our field of useful vision gradually narrows, so we can’t take in as much in one glance as we used to. As bad as peripheral vision is in young adults with normal vision, it gets worse with age.
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