Its far from real. Its overly exagerated. I had glasses in the past and I can tell I never had problems with lens flare efects or dirt.
When your glasses get dirty, the dirt pattern will be different on left vs rigth so the brains comes in and will compensate the image, and because the focus is far from your lenses the eye which was affected will get a blurred image, so overall u will get blurry images.
2nd the lens flare effect u get moslty on multiple lenses like cameras hense the multiple consecutive spots. If its rainy and u got rain drops on your lenses u get the effect but u can also see the raindrops.
3rd even if u are in a dogfight if u cant see anything because of dirt u take cover and clean it a little in 2-3sec.
Mostly this effect doesnt bothered but there some occasion (not few) when they was tearing my eyes out. It didnt bodered me when the enemies came with flashlights and my monitor was all white, that was something close to realism, but the lens flare effect its far from real.