Illusions are not just your misperceptions "about" something.
An illusion is something which appears to be there, but which is not really there. It only appears to be there because you have lost sight of the whole picture, are lacking some information, and have taken something out of context.
Yes, in terms of your misperceptions, it could be that you are projecting something onto what's there, having illusions about it, seeing something "in" it that isn't there.
But illusions are more than just your misperceptions. And they don't only take place inside your head. They occur outside of you as well.
The body's eyes, look upon an illusion, and as if it is really there. The world, Earth, is an illusion. It is a picture of something existing that doesn't exist.
"Who is afraid to look upon illusions, knowing his Savior stands beside him?"
"Be not deceived by the illusions it presents of size and thickness, weight, solidity, and firmness of foundation. Yes, to the body's eyes it looks like an enormous, solid body, immovable as is a mountain."
"Sin is a block, set like a heavy gate, locked and without a key, across the road to peace. 3 No one who looks on it without the help of reason would try to pass it. 4 The body's eyes behold it as solid granite, so thick it would be madness to attempt to pass it."
"Everything the body's eyes can see is a mistake, an error in perception, a distorted fragment of the whole without the meaning that the whole would give."
"The body's eyes see only form. 4 They cannot see beyond what they were made to see. 5 And they were made to look on error and not see past it. 6 Theirs is indeed a strange perception, for THEY CAN SEE ONLY ILLUSIONS, unable to look beyond the granite block of sin, and stopping at the outside form of nothing. "
"See how the body's eyes rest on externals and cannot go beyond."
Since the body's eyes can ONLY see illusions, and since the body's eyes CAN SEE PLANET EARTH, planet Earth MUST BE AN ILLUSION!
The world itself, is an illusion. And that means it is presenting to you a temptation to believe that something is there, something is happening, which is not happening. If you fall for the illusion, you will think the world is real. If you recognize the illusion for what it is, you will not fall for it and will see past it or "see through" its deception.
To see through a deception you need to see the bigger picture.
If for example you have a puzzle, and before you solve the puzzle you do not know the answer, you are deceived by the form of the puzzle. Maybe it's some 3d puzzle with blocks or something that you have to twist just the right way to get them to unlock. You mess with it for hours trying to figure it out. Then finally you suddenly have an awakening and SEE the TRICKERY that was being used to deceive you, and you suddenly realize how to overcome the illusion. You solve the puzzle instantly. And no longer are you deceived by the illusion that it was something else.
It's the same with the world. Earth is an illusion. Believing it is real is false perception. The body's eyes were made to SEE IT as if it's really there and believe it's real. You have to learn the body's eyes are lying to you. And you need a different kind of vision - Christ Vision - to help you to see the bigger picture BEYOND the illusion, so that you can recognize that the illusion is a deception. Only then can you be free of illusions, because the world itself is an illusion.
Your misperceptions of the world are your inability to recognize that *IT* is an illusion. They are illusions on top of illusions. When you perceive the world correctly you will recognize it is an illusion, not a reality. And illusions do not really exist. There is no world.