Okay, I've noticed that red-text-on-blue-background or vice-versa is super hard to read, because our eyes have quite a bit of chromatic aberration and can't foc

Okay, I've noticed that red-text-on-blue-background or vice-versa is super hard to read, because our eyes have quite a bit of chromatic aberration and can't focus on both ends of the spectrum at the same time. So is it perhaps just training the eye to focus on the red end rather than the blue end, as a sort of exercise? (Also, did you ever notice that optometrists' signs are always deep blue, and thus hard to focus on? Ope, can't even see the sign, better head in and get an exam!)