What causes it??

I seem to get it a lot lately. My vision dims so its like im wearing sunglasses in the house

It seems to sort itself out if i go to sleep.

Is it an exhaustion thingy or should i be worrying and going to GP???

Ive also noticed driving at night on dark lanes im almost always blinded by oncoming cars. Now is that just the fact everyones got the new generation headlamps or am i going night blind???

Any ideas?? Im hoping its tiredness and maybe vitamins or something simple!!