On diagnosis I was advised just not to treat false hypos, which was easier said than done because I did probably come close to passing out at 9 ish, but I was 30ish on diagnosis, so my body incorrectly thought 9 was low. But getting to feel ok at normal levels does mean effectively training your body to get used to the normal levels. If you get to a point where you feel like you need to treat a hypo but you know youre not actually hypo could you try extending the period you stay down there, if your safe and at home and not doing anything you might feel a bit rubbish but you'll be teaching your body that it's a normal level that it doesn't need to panic about. Or you need to adjust your targets so you come down in steps, if your currently running so high you have false hypos at 9-10 then set your target as 12-14, once you get used to that aim to be 9-12, then aim for 7-9, then you can aim for the actual target of 4-7.
The blurry vision at normal levels is just temporary, as your body gets used to normal levels your eyes will get used to it to. It might take a couple of weeks for your eyes to get used to it, but they will. Running at high levels does carry risks of rather more long term adverse impacts on your vision.