i know this, but i dont have a solution. i noticed this in winter times being much worse than in summer times. as soon as the sun goes down my vision gets significant more blurry. probably shorter daylight makes eyes more strained. i dont know what your reason for blurry vision is as the reasons can be many. (of course energy deficiency aka exhaustion is always a possible reason)
in my case i got a infrared light i use in winter to warm me but it seams that it somehow makes my eyes a bit worse.
in general, vitamin A as retinol helps with eye health especially if you are seeing worse in dark. also vitamin D is required as it works in tandem with vitamin A. and zink which is part of the VDR receptor as is retinol and D.
what also could help is to get a sleeping mask as total darkness might help your eyes regenerate. i read recently a article about how artificial city lights increased occurances of AMD (macular degeneration).
also problems with your eyes cornea, like being dry or bad fluid or fat film can lead to this. i suffered hard from this last year were i temporarly had so blurry vision on that one eye which somehow suffered to hot dry air drag but not the other, that i would see even worse as if i had my glasses off, for like 30-40minutes until it normalized.
indicative for this kind of problem is when you see fine at first, but then blink and suddenly it gets blurry or worse or the other way it gets better with blinking.
there are special fat based drops which might help to stabilize fat film on your eye.
also cleaning eyes with a damp warm cloth might help. as it helps your eyes secrete fluids better necessary to maintain the fat film on your eyes.
the reasons your cortisone creme might have worked are many. you can try some low dose cortisol like hydrocortisol and see if this works too. maybe adrenal exhaustion is a problem for you.
for that cortisol or sodium, vitamin c and b5 might help.
also it could be inflammatory, in that case higher dose vitamin D (in combination with A and zink) might work too.
