I have progressive myopia. I grew up with perfectly normal eyes but slowly started getting myopic.
The thing is, my brain knows (or should know) what the world looks like -- it knows that far away objects do not suddenly blur. So when the input from the retina changes, why doesn't the brain correct it in perception?
I'm assuming here that this should work by the same principles as size and colour constancy. In both cases the input from the retina is different but the brain doesn't perceive it as an actual change in size or colour.