For some great illustrations of this I recommend people take a look at the Nova episode "Your Brain: Perception Deception" [1]. Nova episodes usually are only available to watch for free for a couple months after they air, then you have to be a PBS contributor, but occasionally old episodes become temporarily available. This one happens to be available now, with the video embedded at the link I gave.
The whole thing is worth watching, but for the material most directly relevant to this you can start at the 7:13 minute mark, where it briefly discusses a well known optical illusion and why it works, and then looks at the question of if you brain can fake your perception so much to make that illusion work, just how much of what you see in normal scenes is real? Then they go into how you only have about 1 degree of high resolution vision at the center.
A couple minutes after that there is a demo showing an interesting way to exploit that. They put the host in an eye tracker that can figure out where she is looking. Then they have her read some text on a monitor and she has no trouble reading. But when the camera shows us the monitor we see that almost the text is just the letter 'X' with small groups of letters briefly switching to other letters and then going back to 'X'.
When we read our eyes don't smoothly scan the text. They actually look at a fixed point for a moment, then jump to another fixed point, and so on (the "saccades" mentioned in the above comment). This isn't just when reading. This is how we look at everything.
She can read the text because the eye tracker is figuring out where she is looking a the software shows the real text there. As soon as her eyes jump that text goes back to 'X'.
When we look at the text and aren't looking exactly where she is we might detect the change to normal text where she is looking but we can't read it because most of the time it will be outside of the small high resolution center of our vision. By the time we can move our eyes down to it her eyes have jumped and that text is back to 'X'.
We don't consciously control the jumps so we can't sync ours to hers, so at best all we can hope for is to occasionally get lucky and maybe get a couple words now and then.
[1] https://www.pbs.org/wgbh/nova/video/your-brain-perception-de...
